Ventana Assay Research Articles

Concordance of Immunohistochemistry and Fluorescence In Situ Hybridization in the Detection of Anaplastic Lymphoma Kinase (ALK) and Ros Proto-oncogene 1 (ROS1) Gene Rearrangements in Non-Small Cell Lung Carcinoma: A 4.5-Year Experience Highlighting Challenges and Pitfalls.

ALK and ROS1 rearrangements are essential biomarkers to be tested in advanced lung adenocarcinomas. While D5F3 Ventana assay is a companion diagnostic for anaplastic lymphoma kinase-targeted therapy, immunohistochemistry is only a screening tool for detecting ROS1 rearrangement. Confirmation by cytogenetic or molecular techniques is necessary. To evaluate the utility of ALK and ROS1 fluorescence in situ hybridization as a complement to immunohistochemistry in routine predictive biomarker testing algorithms. The study was ambispective, spanning 4.5 years during which lung adenocarcinoma samples were subjected to EGFR mutation testing by real-time polymerase chain reaction and ALK/ROS1 rearrangement testing by immunohistochemistry (Ventana D5F3 assay for anaplastic lymphoma kinase protein; manual assay with D4D6 clone for Ros proto-oncogene 1 protein). Fluorescence in situ hybridization was performed in all anaplastic lymphoma kinase equivocal and Ros proto-oncogene 1 immunopositive cases. Of 1874 samples included, EGFR mutations were detected in 27% (481 of 1796). Anaplastic lymphoma kinase immunohistochemistry was positive in 10% (174 of 1719) and equivocal in 3% (58 of 1719) of samples tested. ALK fluorescence in situ hybridization showed 81% (77 of 95) concordance with immunohistochemistry. Ros proto-oncogene 1 immunopositivity was noted in 13% (190 of 1425) of cases, with hybridization-confirmed rearrangements in 19.3% (26 of 135) of samples, all of which showed diffuse, strong- to moderate-intensity, cytoplasmic staining in tumor cells. Ros proto-oncogene 1 protein overexpression without rearrangement was significantly common in EGFR-mutant and ALK-rearranged adenocarcinomas. Immunostaining is a robust method for ALK-rearrangement testing, with fluorescence in situ hybridization adding value in the rare equivocal stained case. ROS1-rearrangement testing is more cost-effective if immunohistochemistry is followed by fluorescence in situ hybridization after excluding EGFR-mutant and ALK-rearranged adenocarcinomas.

Abstract OT2-10-03: HCRN BRE 19-433: A Multi-institutional Phase II Study to Evaluate Efficacy and Safety of TAlazoparib, Radiotherapy and Atezolizumab in gBRCA 1/2 negative Patients with PD-L1+ Metastatic Triple Negative Breast Cancer (TARA)

Abstract Background Although immunotherapy (IO) in combination with chemotherapy has improved progression free and overall survival in patients with PD-L1+ metastatic triple negative breast cancer (mTNBC), prognosis remains poor. A potential therapeutic strategy to restore sensitivity to IO in patients with progressive disease is to introduce agents that re-sensitize the immune system to IO leading to a more tumor-specific and less toxic treatment in the second-line setting or beyond. Both talazoparib, a PARP inhibitor, and radiation (XRT) independently increase PD-L1 expression on the tumor cell surface resulting in heightened sensitivity to IO agents like atezolizumab, a PD-L1 inhibitor. Although a local treatment, XRT has the ability to produce an abscopal effect resulting in systemic shrinkage of non-irradiated tumors outside/distant to the XRT field, a phenomenon observed in patients receiving concurrent IO. While talazoparib is standard treatment in patients with gBRCA1 and 2 mutations, it is also a potent radiosensitizing agent that suppresses homologous recombination and PARP-1-dependent nonhomologous end joining (NHEJ) repair while promoting error-prone alt-NHEJ. When combined with IO, talazoparib can amplify immune responses by generating immunogenic neo-antigens independent of gBRCA1/2 status. We, therefore, hypothesize that the combination of talazoparib, XRT, and atezolizumab will re-sensitize mTNBC tumors to IO and promote a durable tumor-specific response that spares patients from toxicities associated with traditional chemotherapy regimens. Methods This is a Phase II multi-institutional study designed to assess efficacy and safety of talazoparib, high dose XRT, and atezolizumab given in the second-, third-, or fourth-line settings to patients with mTNBC that is PD-L1 positive. A total of 23 patients with mTNBC who do not carry gBRCA pathogenic variants will be enrolled. All patients will be treated with induction talazoparib of 1mg PO daily starting Day 1 of a 28-day cycle. Patients will then receive 8 Gy x 3 fractions to 1-4 metastatic lesions QOD beginning Day 12, 13, or 14. Atezolizumab will be given intravenously (840 mg)) on Day 15 of the 1st cycle and then on Day 1 and Day 15 of the subsequent cycles. Talazoparib and atezolizumab treatment will continue until progression or severe toxicity. The primary endpoint is objective response rate (ORR) in non-irradiated lesions 8 weeks after the first dose of atezolizumab. Key inclusion criteria include biopsy proven mTNBC (ER< 10%, PR< 10%, Her2-) with at least 2 extracranial metastatic lesions. Patients must have at least 1 extracranial metastatic lesion amenable to high dose radiotherapy and at least one additional extracranial lesion of measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST v1.1) that will not receive radiotherapy. Tumors must be PD-L1 positive as defined as >1% on IHC using the SP142 Ventana Assay. Key exclusion criteria include patients with germline BRCA pathogenic variants, more than three previous lines of chemotherapy treatment in the advanced setting with or without IO, and breast cancer progression within the first 3 months of previous IO treatment for non-metastatic or metastatic breast cancer. Sample size was determined using Simon’s 2-stage Minimax design to detect a 20% increase in ORR. The null hypothesis that the true response rate among gBRCA1/2 negative patients of 10% will be tested against a one-sided alternative. Inflammatory cytokines, circulating B cells, and ctDNA will be collected for correlative analysis. Enrollment began in April 2021. The study is managed by the Hoosier Cancer Research Network and is open to accrual at Emory University and University of Alabama at Birmingham. Clinical trial information: NCT04690855 Citation Format: Mylin A. Torres, Kevin Kalinsky, Erica Stringer-Reasor, Ahmed Elkhanany, Jolinta Lin, David M. Schuster, Sarah Friend, Jeffrey Switchenko, Manali Bhave. HCRN BRE 19-433: A Multi-institutional Phase II Study to Evaluate Efficacy and Safety of TAlazoparib, Radiotherapy and Atezolizumab in gBRCA 1/2 negative Patients with PD-L1+ Metastatic Triple Negative Breast Cancer (TARA) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-10-03.

Abstract P4-03-32: Association between androgen receptor expression and recurrence free survival among locally advanced triple negative breast. Real world data from a single Institution in Mexico City

Abstract Background The androgen receptor (AR) is expressed in 12-41% of the TNBC, contributes with differentiation, proliferation, apoptosis, and angiogenesis; its expression is associated with better recurrence free survival (RFS) and overall survival (OS). Objective The aim is to determine the association between AR and pathologic complete response (PCR), recurrence free survival (RFS) in TNBC patients treated with neoadjuvant chemotherapy (neoCT). Patients and methods Cross-sectional, retrospective cohort trial. Adult women with stage II-III TNBC, treated with neoCT from 2014 to 2021 were included. Incomplete medical record, AR not-determined, secondary malignant neoplasm were excluded. AR was determined with the VENTANA assay system, > 1% were considered as positive. Statistical analyses included frequencies and range, comparison was done with X2, cox regression model was made for the prognostic association with a two-sided significance level of 0.05 95% CI. RFS were evaluated with Kaplan Meier method and log-rank test. Results 309 patients were analyzed; AR prevalence was 14.6%. Median age was 49 years (21-87), tumor size was 6.3 cm (0.1-22), ductal histology (95.1%) and nuclear-grade 3 (79%), these findings were not different between the AR+ vs AR-. Median Ki67 was 52% within AR+ vs 65% AR- (p=0.05). All patients were treated with neoCT, 14.9% had disease progression, PCR rates were similar among two groups (48.5% vs 42.2%) p=0.78. At a mean follow up of 19 months, 7 recurrences presented in AR+ (15.5%) vs 67 in the AR- (25.4%) p=NS. Median RFS was 54.9 (IC 95% 45.2-64-6) and 65.5 months (IC 95% 60.4-70.7), p=0.3. We analyze the prognostic factors, for RFS we found statistically significant the locally advanced stage OR 5.6 (1.4-22.9), residual cancer burden (RCB) OR 2.8 (2.1-3.9), N stage OR 1.4 (1.1-1.8) and progression during neoCT OR 2.8 (1.5-5.1); and for OS the RCB OR 2.8 (1.9-4.1) and progression during neoCT OR 3.1 (1.5-6.9). Conclusions In this trial the AR expression did not show significant association neither with PCR and RFS; main reasons are the low prevalence of AR expression, high rate of disease progression and high residual cancer burden after neoCT. We found association with other known factors (RCB, N stage, progression during neoCT and locally advanced stage), which are more important factors that determine the bad prognosis of TNBC. Citation Format: Eder Araiza Alvarado, Claudia Haydee Arce Salinas. Association between androgen receptor expression and recurrence free survival among locally advanced triple negative breast. Real world data from a single Institution in Mexico City [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-32.

Abstract 5135: Antitumor activity of dostarlimab by PD-L1 and tumor mutation burden (TMB) in patients (pts) with mismatch repair deficient and proficient (dMMR and MMRp) tumors in the GARNET trial

Abstract Background: Dostarlimab is a programmed death 1 (PD-1) inhibitor approved as monotherapy in pts with dMMR recurrent/advanced endometrial cancer (EC) that has progressed on or following treatment with a platinum-containing regimen or solid tumors that have progressed on or following prior treatment, with no satisfactory alternative treatment options. Here we report on a post-hoc analysis of antitumor activity by PDL1 expression and TMB in pts with dMMR and MMRp solid tumors in the GARNET trial. Methods: GARNET (NCT02715284) is a phase 1, multicenter, open-label, single-arm study of dostarlimab in pts with advanced/recurrent solid tumors. Three expansion cohorts enrolled pts based on MMR status: dMMR (A1) and MMRp (A2) advanced/recurrent EC, and dMMR non-EC solid tumors (F). Pts received dostarlimab 500 mg IV Q3W for 4 cycles, then 1000 mg IV Q6W until progression or discontinuation. TMB and PDL1 were exploratory biomarkers. TMB status was determined by Foundation One test; TMB-high (TMB-H) was defined as ≥10 mutations/Mb. PDL1 expression was determined by combined positive score (CPS) by Ventana assay; PDL1-high (PDL1-H) was defined as CPS ≥1. The study was not powered to assess antitumor activity within subgroups. Results: TMB-H and PDL1-H were common in dMMR solid tumors; PDL1-H was observed in 39.4% of MMRp EC tumors (Table). Objective response rate (ORR) was higher in pts with TMB-H/PDL1-H tumors (55.6% for all cohorts, combined; Table). Safety for each cohort was previously reported.1 Conclusions: PDL1-H and TMB-H were frequently observed in the dMMR EC and non-EC cohorts, regardless of tumor type; PDL1-H was also prevalent in MMRp EC tumors. Although not powered to assess antitumor activity, ORR by BICR per RECIST v1.1 was higher in pts with TMB-H and PDL1-H solid tumors. Across cohorts, dMMR status was predictive of response. 1.Andre T, et al. Ann Oncol 2021;32(suppl 5):S829-S866. 991P. Table A1(dMMR EC)N=103 F(dMMR non-EC)N=106 A1+F(dMMR combined)N=209 A2(MMRp EC)N=142 A1+A2+F (Total)N=351 Biomarker distribution, n (%) TMB High 85 (82.5) 79 (74.5) 164 (78.5) 9 (6.3) 173 (49.3) Low 13 (12.6) 9 (8.5) 22 (10.5) 129 (90.8) 151 (43.0) Unknown 5 (4.9) 18 (17.0) 23 (11.0) 4 (2.8) 27 (7.7) PD-L1 High 56 (54.4) 52 (49.1) 108 (51.7) 56 (39.4) 164 (46.7) Low 23 (22.3) 17 (16.0) 40 (19.1) 45 (31.7) 85 (24.2) Unknown 24 (23.3) 37 (34.9) 61 (29.2) 41 (28.9) 102 (29.1) ORR by BICR per RECIST v1.1, n/N (%, 95% CI)a Overall 46/103(44.7, 34.9–54.8) 41/106(38.7, 29.4–48.6) 87/209(41.6, 34.9–48.6) 19/142(13.4, 8.3–20.1) — TMB-L/PDL1-L (L/L) 1/5(20.0, 0.5–71.6) 1/3 (33.3, 0.8–90.6) 2/8(25.0, 3.2–65.1) 2/43(4.7, 0.6–15.8) 4/51(7.8, 2.2–18.9) TMB-L/PDL1-H (L/H) 2/5(40.0, 5.3–85.3) 1/2(50.0, 1.3–98.7) 3/7(42.9, 9.9–81.6) 7/50(14.0, 5.8–26.7) 10/57(17.5, 8.7–29.9) TMB-H/PDL1-L (H/L) 5/17(29.4, 10.3–56.0) 3/14(21.4, 4.7–50.8) 8/31(25.8, 11.9–44.6) 0/1(0, 0–97.5) 8/32(25.0, 11.5–43.4) TMB-H/PDL1-H (H/H) 29/50(58.0, 43.2–71.8) 22/43(51.2, 35.5–66.7) 51/93(54.8, 44.2–65.2) 4/6(66.7, 22.3–95.7) 55/99(55.6, 45.2–65.5) aOnly those pts with both known TMB status and known CPS were included in ORR calculations Citation Format: Thierry André, Susana Banerjee, Dominique Berton, Susan L. Ellard, Begoña Jimenez, Vanessa Samouëlian, Lucy Gilbert, Valentina Boni, Xinwei Han, Grace Antony, Jennifer Veneris, Ana Oaknin. Antitumor activity of dostarlimab by PD-L1 and tumor mutation burden (TMB) in patients (pts) with mismatch repair deficient and proficient (dMMR and MMRp) tumors in the GARNET trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5135.

Abstract P2-14-18: A randomized phase II trial of carboplatin with or without nivolumab in metastatic triple-negative breast cancer

Abstract Background: Platinum agents induce DNA crosslinking and cause accumulation of genotoxic stress, which leads to immune activation via IFN-γ signaling, making the combination with nivolumab (PD-1 antibody) an attractive strategy to enhance the benefit of either agent alone in metastatic triple-negative breast cancer (mTNBC). Methods: In this phase II open-label, investigator-initiated, multicenter trial, patients with unresectable locally advanced or mTNBC treated with 0-1 prior lines of chemotherapy in the metastatic setting were randomized 1:1 to carboplatin (AUC 6) with or without nivolumab (360 mg) IV every 3 weeks. Stratification factors included: germline BRCA (gBRCA) status, prior neo/adjuvant platinum, and number of prior lines of metastatic therapy. After approval of PD-L1 inhibition for mTNBC, the study was amended to include first-line mTNBC only and PD-L1 status was added as a stratification factor. Patients randomized to carboplatin alone were allowed to crossover at progression to receive nivolumab (+ nab-paclitaxel post-amendment). The primary objective was to compare progression-free survival (PFS) per RECIST 1.1 criteria of carboplatin with or without nivolumab in first-line mTNBC in the intent-to-treat (ITT) population. Key secondary objectives were objective response rate (ORR), overall survival (OS), clinical benefit rate, and duration and time to objective response. PD-L1 status was confirmed centrally using the SP142 Ventana assay (positive, ≥1% IC). Paired research biopsies at baseline, on-treatment and at progression were performed, if safely accessible. The trial closed to accrual prior to reaching target accrual due to approval of PD-1 inhibition in combination with platinum-based chemotherapy for PD-L1+ mTNBC. Results: Between 1/30/2018 and 12/9/2020, 78 patients enrolled. Three patients did not receive protocol treatment, and the safety analysis was conducted among the 75 that received any treatment; 37 received carboplatin + nivolumab (Arm A), 38 received carboplatin alone (Arm B). Median age was 59.1 yrs (range: 25.4-75.8). Four patients (5.3%) had a known gBRCA1/2 mutation. Sixty-two (82.7%) patients received 0 prior lines (ITT population) and 13 (17.3%) 1 prior line of metastatic therapy. Sixty-seven patients (89.3%) experienced any grade ≥2 treatment-related adverse event (AE). The most frequent AE were platelet count decrease (n=40; 53.3%), anemia (n=36; 48.0%), neutrophil count decrease (n=33; 44.0%) and fatigue (n=24; 32.0%). Grade 3/4 AE were observed in 46 (61.3%) patients, and there was one grade 5 AE (COVID19 pneumonia). Any grade ≥2 immune-related AE (irAE) were observed in 25 of the 37 (67.6%) patients treated with carboplatin + nivolumab. Grade 3/4 irAE were observed in 11 (29.7%) patients. In the ITT population (32 on Arm A; 30 on Arm B), median PFS was 4.2 months with carboplatin + nivolumab, and 5.5 months with carboplatin (stratified HR 0.98, 95% CI [0.51 - 1.88]; p=0.95). ORR was 25% vs. 23.3%, respectively. At a median follow-up of 23.5 months, median OS was 17.5 months vs. 10.7 months (stratified HR 0.63, 95% CI [0.32 - 1.24]; p=0.18). In patients with PD-L1+ mTNBC (13 on Arm A; 11 on Arm B), median PFS was 8.3 months and 4.7 months, respectively (stratified HR 0.63, 95% CI [0.21 - 1.89]; p=0.41). ORR was 23.1% vs. 27.3%, respectively. Median OS was 17.5 months vs. 9.6 months (stratified HR 0.59, 95% CI [0.20 - 1.75]; p=0.34). Conclusions: Addition of nivolumab to carboplatin in patients with previously untreated mTNBC, unselected by PD-L1 status, did not significantly improve PFS. A trend toward improved PFS and OS was observed in patients with PD-L1+ mTNBC. Tissue, blood and intestinal microbiome biomarker analyses are planned; bulk tumor and single-cell sequencing, and TCR sequencing in peripheral blood are ongoing. Clinical trial information: NCT03414684. Citation Format: Ana C Garrido-Castro, Noah Graham, Kevin Bi, Jihye Park, Jingxin Fu, Tanya Keenan, Edward Thomas Richardson, Ricardo Pastorello, Paulina Lange, Victoria Attaya, Robert Wesolowski, Natalie Sinclair, Zarah Lucas, Steve Lo, Nadine Tung, Meredith Faggen, Peter A Kaufman, Caroline C Block, Fred Briccetti, Madhavi Toke, Wendy Chen, Kai Wucherpfennig, Sascha Marx, Ye Tian, Judith Agudo, Jennifer L Guerriero, Stuart Schnitt, Nancy U Lin, Eric P Winer, Elizabeth A Mittendorf, Nabihah Tayob, Eliezer Van Allen, Sara M Tolaney. A randomized phase II trial of carboplatin with or without nivolumab in metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-14-18.

P59.27 Complementary Utility of Combined ALK/ROS1 FISH with Immunohistochemistry for ALK/ROS1 Rearrangement Testing in Lung Cancer

Testing for EGFR mutations, ALK and ROS1 rearrangements and BRAF mutations are now recommended as the essential minimum predictive biomarkers to be tested in primary non-squamous NSCLC patients presenting with advanced disease. While the ALK D5F3 Ventana immunohistochemistry (IHC) Assay is approved for detection of ALK rearrangements and for targeted therapy, ROS1 IHC only serves as a screening tool for ROS1 rearrangements with demonstration of gene fusions by molecular methods required for confirmation and targeted treatment. Nevertheless, equivocal IHC results, although uncommon, still occur with the D5F3 ALK assay necessitating complementary methods for confirmation. The recent availability of combined ALK/ROS1 break-apart fluorescence in-situ hybridisation (FISH) probes offer the advantage of tissue conservation with ability to analyse both gene alterations in a single tissue section. The aim of the present study was to study the utility of the combined ALK/ROS1 FISH assay as a complement to ALK and ROS1 IHC in routine predictive biomarker testing algorithms. Over a 6-year study period, all EGFR wild type NSCLC samples were subject to automated ALK D5F3 Ventana IHC assay and ROS1 IHC using the D4D6 (Cell signalling technology) clone as a manual lab developed test. Diffuse strong granular staining in tumor cells for ALK and ROS1 protein was interpreted as positive. All cases of equivocal ALK staining and positive ROS1 staining was subject to combined ALK/ROS1 FISH using the FlexISH ALK/ROS1 DistinguISH Probe (Vysis) performed as per manufacturers’ instructions. Presence of ALK/ROS1 break apart signals and/or isolated ALK/ROS1 3’ signals in >15% of interpretable tumour nuclei was considered as positive for ALK or ROS1 rearrangement. The ALK Ventana Assay was performed in 711 formalin fixed paraffin embedded EGFR wild type NSCLC samples including biopsies, lymph node excisions and cell blocks. Of these, 12% (85/711) were positive, 2% (13/711) were equivocal, 75% (539/711) were negative, while in the remaining 11% (76/711), result could not be evaluated due to exhaustion of tumor tissue. FISH analysis in four of the ALK IHC equivocal cases show absence of ALK translocations while no tissue remained for FISH analysis in the remaining equivocal cases. ROS1 IHC was performed in 434 cases of the above cohort of which 7% (30/434) were positive. ROS1 immunopositivity was enriched among ALK IHC positive cases with 43% (19/44) of ALK IHC positive cases also showing protein expression of ROS1. FISH analysis revealed ROS1 translocation in two cases (both showing diffuse strong ROS1 protein expression and negative ALK IHC) while all dual ALK/ROS IHC positive cases tested by FISH showed presence of only ALK rearrangements with non-rearranged ROS1 signals. Tissue adequacy remains the major limiting factor for predictive biomarker testing in lung cancer. The use of combined ALK-ROS FISH allows for excellent demonstration of ALK and ROS1 rearrangements in the same section using the same criteria validated in single gene break apart FISH probes. ROS1 protein is commonly overexpressed in ALK rearranged NSCLC and may represent cross reactivity with ALK or a related protein.

BCL2 Expression Identifies a Population with Unmet Medical Need in Previously Untreated (1L) Patients with DLBCL

▪Introduction.High BCL2 protein expression has been associated with inferior outcome in multiple studies in diffuse large B-cell lymphoma (DLBCL) (Gascoyne et al. 1997; Salles et al. 2011; Horn et al. 2013; Tsuyama et al. 2017). Patients with high levels of BCL2 expression may benefit from treatment with venetoclax, a first-in-class, highly selective BCL2 inhibitor with demonstrated activity in cell lines and xenograft models (Souers et al. 2013, Punnoose et al. 2016). The evaluation of BCL2 as a prognostic marker has been complicated by the variability in recognized immunohistochemistry (IHC) thresholds (de Jong et al. 2007; Tsuyama et al. 2017) and the impact of cell-of-origin (COO) (Iqbal et al. 2011). Using a BCL2 IHC scoring algorithm that was developed to identify cell lines that are sensitive to BCL2 inhibition, and that could potentially identify patients likely to benefit from venetoclax, we evaluated the prognostic capability of BCL2 IHC in three independent cohorts of 1L DLBCL patients. Cohorts included two Phase 3 studies (MAIN [NCT00486759] and GOYA [NCT01287741]), and a representative cohort from the British Columbia Cancer Agency (BCCA) registry-based population, in which subjects received chemoimmunotherapy (either rituximab or obinutuzumab, combined with cyclophosphamide, doxorubicin, vincristine and prednisone [CHOP]).Patients and Methods. Pretreatment tumor samples were tested for BCL2 IHC using an algorithm that assesses both the percent of tumor cells stained and the intensity of staining, similar to the BCL2 algorithm proposed by Tsuyama et al. (Table 1).Whole-tissue slides from184 patients from MAIN were tested at Genentech , whole tissue slides from 366 patients from GOYA were tested at Hematogenex (Ventana assay) and tissue microarray slides from 310 patients from BCCA were tested at Ventana (Ventana assay). The NanoString Lymphoma Subtyping gene expression assay was used for classification of COO into germinal center B-cell (GCB), activated B-cell (ABC) or unclassified subtypes in MAIN (n=159), GOYA (n=353) and BCCA (n=302). Multivariate Cox regression analysis of progression-free survival (PFS) was performed in each study with the International Prognostic Index (IPI; The International NHL Prognostic Factors Project 1993) and/or COO as covariates. Given the similar treatment effect, patient data from both treatment arms in each study were merged for this analysis.Results. Baseline characteristics were similar for the BCL2 IHC evaluable and intent-to-treat (ITT) populations of these three cohorts. Prevalence of BCL2 positive patients was 48% in MAIN, 49% in GOYA and 58% in the BCCA cohort. The prevalence of BCL2 positive samples within the ABC subtype was 64%, 75% and 60% in the MAIN, GOYA and BCCA cohorts, respectively, and 40%, 38% and 56% within the GCB subtype, respectively. In univariate analysis, BCL2 positivity was associated with shorter PFS in all three cohorts (Figure 1, A-C). In the MAIN study, the prognostic effect of BCL2 appeared to be in the GCB subgroup, not ABC, as previously reported (Punnoose et al. ASH 2015). In the two largest studies of GOYA and BCCA cohorts, the prognostic effect of BCL2 was similar in ABC and GCB (not shown), and was independent of IPI (Table 2).Conclusions. Using a newly developed BCL2 IHC scoring algorithm, we demonstrate that DLBCL patients positive for BCL2 have a consistently inferior prognosis compared with patients negative for BCL2. The prognostic value of BCL2 IHC is independent of IPI and COO in GOYA and BCCA. The Ventana assay is currently being used in a Phase 2 study of venetoclax in combination with R-CHOP to evaluate the correlation (if any) of BCL2 expression with venetoclax + R-CHOP treatment (CAVALLI - NCT02055820). [Display omitted] DisclosuresSzafer-Glusman:Genentech: Employment. Peale:Genentech / Roche: Employment, Equity Ownership. Lei:Roche: Employment. Ray:Genentech/Roche: Employment. Farazi:Genentech: Employment. Kornacker:Roche: Equity Ownership; F. Hoffmann-La Roche: Employment. Oestergaard:F. Hoffmann-La Roche Ltd: Employment. Liu:F. Hoffmann-La Roche: Employment. Punnoose:Genentech: Employment.

Abstract SP122: Novel biomarkers in immune therapy response

Abstract Four randomized trials demonstrated statistically significant increase in pCR rates when an immune checkpoint inhibitor (ICI) was added to neoadjuvant chemotherapy in triple negative breast cancer (TNBC), these include the KN-522, Impassion-031, I-SPY2 pembrolizumab, and I-SPY2 durvalumab/oleparib arms. One trial, GeparNuevo, showed a non-significant trend for higher pCR rate, and one trial (NeoTrip-aPDL1) showed no effect. In each of these randomized trials, high tumor infiltrating lymphocyte count, high expression of PD-L1 protein and a broad range of immune-related genes and immune gene signatures predicted for higher pCR rate in both chemotherapy alone and chemotherapy plus ICI treatment arms. Unexpectedly, the positive trials also consistently demonstrated that pCR rates significantly improved with ICI therapy even in PDL-1 negative TNBC. For example, in KN-522 the pCR rates were 30% vs 45% in the PDL-1 negative and 55% vs 69% in the PD-L1 positive populations. There is less data on the efficacy of neoadjuvant immune checkpoint therapy in estrogen receptor positive (ER+) cancers. However, both the pembrolizumab and durvalumab + olaparib arms of the I-SPY2 trail demonstrated improvement in pCR rates in ER+ cancers, and these improvements were also independent of PDL-1 mRNA expression or other immune markers. On the other hand, the ER+ MammaPrint ultrahigh (MP2) subset that is characterized by high proliferation, and low ER-related gene expression showed selective benefit from ICI therapy, while no benefit was seen in the MP1 group. The same MP2 group also benefited from adding carboplatin and veliparib to paclitaxel in an earlier arm of I-SPY2 suggesting that among ER+ cancers, the MP2 tumors are more chemotherapy sensitive and this sensitivity might be further enhanced by adding an immune checkpoint inhibitor.A very different biomarker picture emerged from the randomized first line trials in metastatic TNBC (mTNBC). In this clinical setting, the efficacy of immune checkpoint inhibitors (ICI) is proportional to the level of PD-L1 protein expression by immunohistochemistry, or by immune infiltration that can be quantified by tumor infiltrating lymphocyte count. In PDL-1 negative, or immune low, mTNBC no benefit is seen from ICI therapy. In immune rich metastatic TNBC (defined as CPS>20 with 22C3 Assay), close to 30% response rate was seen with single agent pembrolizumab in the KN-199 trial. Two large randomized first line trials, IMpassion-130 and KN-355, demonstrated improved response rates and increased progression free survival (and overall survival in Impassion-130) when ICI was added to nab-paclitaxel (Impassion-130), or taxol or nab-paclitaxel or gemcitabine/carboplatin (KN-355) chemotherapies, respectivel. Impassion-130 also demonstrated that different immunohistochemistry assays for PDL-1 determination have different accuracy to define the atezolizumab sensitive population. The SP142 Ventana assay that defines approximately 40% of the mTNBC population as PDL-1 positive had the highest overall accuracy. A third, and smallest, randomized trial, IMPassion-131, failed to show significant benefit (HR:0.82, p=0.2) from adding atezolizumab to paclitaxel. This failure is likely due to differences in patient composition and limited sample size and power, rather than choice of chemotherapy. Pembrolizumab is also approved in the US for metastatic solid tumors, including breast cancer regardless of receptor status, that have either microsatellite instability, or high tumor mutation burden (>10 mutation /MB). Few trials examined the role of ICI in ER+ metastatic breast cancer, and these studies showed low single agent activity. Due to the paucity of data, the relationship between immune therapy efficacy and PDL-1 expression, or recurrence score, or luminal A versus B subtype is unknown in ER+ metastatic disease. Citation Format: L Pusztai. Novel biomarkers in immune therapy response [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP122.

Comparability of laboratory-developed and commercial PD-L1 assays in non-small cell lung carcinoma

PD-L1 expression in non-small cell lung cancer (NSCLC) is predictive of response to treatment with PD-1 and PD-L1 inhibitors. Different inhibitors have been developed with different PD-L1 assays, which use different PD-1 antibody clones on different immunohistochemistry platforms. Depending on instrument and reagent availability, laboratory-developed tests with cross-platform use of PD-L1 antibodies may have practical benefits over commercial assays. The 22C3 pharmDx Assay (referred to as 22C3 DAKO), the VENTANA PD-L1 SP263 Assay (referred to as SP263 VENTANA) and a lab-developed test using the 22C3 antibody on the VENTANA BenchMark ULTRA IHC/ISH system (referred to as 22C3 VENTANA) were performed on whole sections of 85 NSCLC surgical resections. All sections were independently scored by three pathologists using tumor proportion scores. Correlation coefficients for continuous scores in pairwise comparisons between assays ranged from 0.976 to 0.978. When using a 1% positivity threshold (dichotomous scores), the 22C3 DAKO assay and 22C3 VENTANA assays showed the greatest agreement (93% agreement, κ = 0.86, 95% CI 0.75–0.97), and the 22C3 DAKO and SP263 VENTANA assays tended to show slightly less agreement (84% agreement, κ = 0.66, 95% CI 0.50–0.82). When using a 50% positivity threshold (dichotomous scores), all pairwise comparisons showed similar agreement (96–99% agreement, κ = 0.89–0.97). Overall, there was no significant difference between assays at 1% or 50% thresholds (P = .77). These data are consistent with potential interchangeability of these assays, which may widen the scope of PD-L1 assays available to laboratories and reduce logistical barriers to testing.

Abstract P6-09-20: Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival

Abstract Introduction: Hormone receptors ER and PgR are routinely assessed by pathologists using immunohistochemical (IHC) assays to guide treatment decisions. Patients who are hormone receptor positive are offered hormonal therapy, such as tamoxifen, which improves survival. Although both ER and PgR are evaluated, ER is primarily utilized for patient management as the clinical utility of PgR has not been clearly established according to CAP/ASCO guidelines. Notably, a meta-analysis by the Early Breast Cancer Trialists' Collaborative Group reported that PgR status was not significantly predictive of response to adjuvant tamoxifen, suggesting that PgR may not have a role in breast cancer management. More recently, the level of PgR expression has been hypothesized to be important in predicting response to endocrine therapy, where high PgR levels are more indicative of estrogen-dependent tumors, and thus more sensitive to hormonal treatment. In this study, we evaluate PgR expression using the current cut-point (Allred>2), as well as an optimized cut-point (Allred>5 to identify PgR high tumors), with regards to 15yr disease-free survival (DFS) and disease-specific overall survival (DSOS) using three commercially available ready-to-use (RTU) IHC assays from Dako, Leica and Ventana in an ER+ cohort. Methods: The Calgary tamoxifen breast cancer cohort (Calgary cohort) is a TMA series that includes 532 patients diagnosed with primary breast cancer (1985-2000) who received tamoxifen treatment regardless of hormone receptor status. All RTU assays followed vendor recommended protocols. Specific details regarding the cohort and IHC assays have been previously described (Kornaga et al. Mod Path 2016). All analyses were performed using Stata 12, and multivariate models were adjusted for age, grade, size, lymph node and HER2 status. ER status was defined by the corresponding vendor specific IHC assay. Results: Multivariate models looking at DFS are presented in Table 1. None of the assays were significant when the clinical cut-point was used; however, when the optimized cut-point was investigated, all assays found high expression of PgR was significantly associated with improved DFS. Table 2 presents the multivariate models looking at DSOS. Similarly, PgR was not found to be associated with improved DSOS using the current cut-point. When the optimized cut-point was examined, Dako and Leica assays were significantly associated with improved DSOS: The Ventana assay did not reach significance. Table 1 PgR15YR DFS CutpointHR95% CIp-valueDako>20.830.40-1.730.624Dako>50.560.35-0.910.020Leica>21.130.45-2.830.792Leica>50.520.30-0.890.017Ventana>20.730.32-1.670.460Ventana>50.570.34-0.970.037 Table 2 PgR15YR DSOS CutpointHR95% CIp-valueDako>20.740.33-1.650.464Dako>50.550.32-0.950.031Leica>20.880.35-2.220.780Leica>50.440.24-0.790.006Ventana>20.590.25-1.370.218Ventana>50.630.35-1.150.134 Conclusions: High PgR expression (Allred>5) is associated with improved 15yr DFS and DSOS in a tamoxifen-treated cohort, where PgR positivity defined using current guidelines is not associated with improved DFS or DSOS. Additionally, differences were noted between the vendor RTU assays with regards to DSOS. Citation Format: Kornaga EN, Paterson AHG, Feng X, Morris DG, Magliocco AM, Klimowicz AC. Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-20.

PL04a.04: Multicentric French Harmonization Study for PD-L1 IHC Testing in NSCLC

PD-L1 immunohistochemistry (IHC) is considered as a predictive biomarker for most anti PD-1/PDL-1 therapies in non-small cell lung cancer, but different assays were used in clinical trials. Several studies have compared 4 assays (22C3, 28-8, SP142, SP263) performed in central laboratories on dedicated platforms. In order to harmonize and make PD-L1 testing widely available on most IHC platforms and centers, we compared PD-L1 Dako (22C3, 28-8) and Ventana (SP263) assays and laboratory-developed tests (LDT). IHC with five anti-PD-L1 clones (28-8, 22C3, E1L3N, SP142 and SP263) was performed concomitantly on 41 NSCLC surgical specimens in 7 centers. The IHC platforms used were Ventana BenchMark Ultra (2 centers), Leica Bond (2 centers) or Dako Autostainer Link 48 (3 centers). For each matching platform, 22C3, 28.8 and SP263 assays were performed. For non-matching platforms and other antibodies, LDT were developed in each center and harmonized based on tonsil tissue staining. A total of 35 stainings were performed across different platforms and antibodies for each case. Seven thoracic pathologists trained to PD-L1 scoring in expert courses participated. Each pathologist analyzed 6 cases and compared the stainings obtained with the 5 antibodies on all platforms. Tumor cell and immune cell D-L1 stainings were scored semi-quantitatively as recommended in PD-L1 Dako and Ventana assays. For statistical analysis, 1, 5, 25, 50% and 1, 5, 10% thresholds were used for tumor cells and immune cells, respectively. 28-8, 22C3 and SP263 assays were highly concordant for tumor cell and immune cell stainings across the 5 Dako or Ventana platforms (R2=0.886 to 0.953). LDT demonstrated various levels of concordance as compared to those 3 assays. Notably, LDT using SP263 clone were the most concordant across all platforms for both immune cell and tumor cell stainings, whereas some selected LDT with clones 28-8, 22C3 and E1L3N, but not SP142, showed a good correlation with the 3 assays regarding tumor cells only. 28-8, 22C3 and SP263 assays gave comparable results across dedicated platforms for tumor cells staining, as well as some selected LDT protocols using 28-8, 22C3, SP263 and E1L3N clones. These results will be further validated at the national level in order to provide recommendations for the use of assays and LDT for PD-L1 testing in NSCLC.

Anaplastic lymphoma kinase immunohistochemistry in lung adenocarcinomas: Evaluation of performance of standard manual method using D5F3 antibody.

Immunohistochemistry (IHC) with anaplastic lymphoma kinase (ALK) antibodies is considered as an economical screening method in lung adenocarcinomas. Automated Ventana D5F3-IHC is approved by US Food and Drug Administration for targeted therapy; however, the automated IHC apparatus are not widely used in most laboratories. We evaluated the performance of ALK IHC using the manual semiquantitative method to assess the concordance with Ventana ALK IHC assay. We tested 156 cases of primary lung adenocarcinomas for ALK protein expression by D5F3-IHC. The intensity of cytoplasmic staining was classified as 0 or 1+/2+/3+ (weak/medium/strong). Binary score of positive and negative was used for Ventana assay. A comparison analysis and clinicopathological features were recorded. ALK IHC was positive in 25 (16.02%) cases, of which 18 were men and mostly nonsmokers. The mean age for all patients was 55 years, and for ALK IHC-positive cases was 48 years. Nine of 25 (36%) ALK IHC-positive cases showed signet ring cell and mucinous morphology. On comparison, all, but one, cases positive by manual method showed positive results by automated assay. IHC negative cases by manual method were negative by Ventana assay. Manual IHC is equally effective in the detection of ALK-rearranged cases as automated methods. It can be easily integrated as a screening method into routine practice thus reducing the cost of automated systems. However, equivocal cases should be tested by approved methods.

Evaluation of three commercial progesterone receptor assays in a single tamoxifen-treated breast cancer cohort

Estrogen receptor and progesterone receptor status are routinely assessed using immunohistochemistry assays to assist in patient prognosis and clinical management. Three commonly utilized autostainer vendors—Dako, Leica and Ventana—provide ready-to-use progesterone receptor assays; however, they have never been directly compared in a single breast cancer cohort. We looked at three immunohistochemical progesterone receptor assays, in addition to original ligand-binding assay results, in a single retrospective, tamoxifen-treated breast cancer cohort to investigate inter- and intra-observer agreement, concordance, prognostic ability and measures of test performance. All immunohistochemical assays utilized the manufacturer's specified protocols. Five-year disease-free survival was the endpoint of interest, and multivariate models were adjusted for lymph node status, tumor grade, tumor size and human epidermal growth factor 2 status. All assays showed substantial to almost perfect agreement between the three observers (Dako κ=0.69–0.90; Leica κ=0.70–0.89; and Ventana κ=0.78–0.94) and concordance (Dako/Leica κ=0.81; Dako/Ventana κ=0.78; and Leica/Ventana κ=0.82). Univariate survival analyses showed that only the ligand-binding assay, Dako and Ventana assays achieved statistical significance. No statistically significant results were seen in multivariate models, although a strong trend was seen with the Ventana progesterone receptor assay. All assays performed similarly with regards to measures of test performance with ligand-binding assay set as the reference, and all immunohistochemical assays outperformed the ligand-binding assay in regards to 5-year disease-free survival. Despite similar agreement and concordance with the progesterone receptor assays, clear differences were noted with regards to 5-year disease-free survival. Additional survival analyses suggest that clinical utility of estrogen receptor assays vary when investigated in combination with progesterone receptor.

A Harmonization Study for the Use of 22C3 PD-L1 Immunohistochemical Staining on Ventana’s Platform

IntroductionImmunotherapy is a novel treatment for lung cancer. Pembrolizumab (Merck Sharp and Dohme, Kenilworth, NJ) is a monoclonal antibody against programmed cell death 1 that has been approved for use with NSCLC together with a companion diagnostic by Dako (Carpinteria, CA). Ventana's BenchMark XT (Ventana Medical Systems, Tucson, AZ) is a widely used immunohistochemical (IHC) platform. However, data on its reliability and reproducibility with the 22C3 antibody are scant. MethodsWe performed a comprehensive calibration of 22C3 programmed cell death ligand 1 (PD-L1) staining on the BenchMark XT platform using Dako’s prediluted 22C3 anti–PD-L1 primary antibody with two of Ventana’s detection systems. Forty-one random cases of NSCLC were then independently evaluated by two pathologists. Each case was scored using Dako- or Ventana-stained slides. The scores obtained with the two 22C3 Ventana assays were compared with those obtained using the Dako 22C3 IHC platform. ResultsThe Dako IHC platform stratified eight, seven, and 26 cases as being strongly positive, weakly positive, and negative for PD-L1, respectively, whereas 36 of 41 cases (87.8%) had the same results with Ventana’s UltraView 22C3 protocol (Pearson’s correlation score 0.91, p < 0.0001). Moreover, 35 of 41 cases (85.3%) had the same results with Ventana’s OptiView 22C3 protocol (Pearson’s correlation score 0.89, p < 0.0001). ConclusionsThe results of this study demonstrate that the same PD-L1 IHC algorithm can be reliably applied to Ventana's BenchMark XT platform. Furthermore, we were able to detect all of the strongly positive cases with high interobserver and intraobserver agreement by using the Ventana platform. These findings suggest that the Ventana platform can be used to stratify patients for pembrolizumab-based immunotherapy.

Inconsistent results in the analysis of ALK rearrangements in non-small cell lung cancer.

BackgroundIdentification of targetable EML4-ALK fusion proteins has revolutionized the treatment of a minor subgroup of non-small cell lung cancer (NSCLC) patients. Although fluorescence in situ hybridization (FISH) is regarded as the gold standard for detection of ALK rearrangements, ALK immunohistochemistry (IHC) is often used as screening tool in clinical practice. In order to unbiasedly analyze the diagnostic impact of such a screening strategy, we compared ALK IHC with ALK FISH in three large representative Swedish NSCLC cohorts incorporating clinical parameters and gene expression data.MethodsALK rearrangements were detected using FISH on tissue microarrays (TMAs), including tissue from 851 NSCLC patients. In parallel, ALK protein expression was detected using IHC, applying the antibody clone D5F3 with two different protocols (the FDA approved Ventana CDx assay and our in house Dako IHC protocol). Gene expression microarray data (Affymetrix) was available for 194 patients.ResultsALK rearrangements were detected in 1.7 % in the complete cohort and 2.0 % in the non-squamous cell carcinoma subgroup. ALK protein expression was observed in 1.8 and 1.4 % when applying the Ventana assay or the in house Dako protocol, respectively. The specificity and accuracy of IHC was high (> 98 %), while the sensitivity was between 69 % (Ventana) and 62 % (in house Dako protocol). Furthermore, only 67 % of the ALK IHC positive cases were positive with both IHC assays. Gene expression analysis revealed that 6/194 (3 %) tumors showed high ALK gene expression (≥ 6 AU) and of them only three were positive by either FISH or IHC.ConclusionThe overall frequency of ALK rearrangements based on FISH was lower than previously reported. The sensitivity of both IHC assays was low, and the concordance between the FISH and the IHC assays poor, questioning current strategies to screen with IHC prior to FISH or completely replace FISH by IHC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2646-x) contains supplementary material, which is available to authorized users.

Abstract A55: Phase 1 results of emibetuzumab (LY2875358), a bivalent MET antibody, in patients with advanced castration-resistant prostate cancer, and MET positive renal cell carcinoma, non-small cell lung cancer, and hepatocellular carcinoma

Abstract Background: Activation of the hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor receptor (MET) pathway promotes tumor growth, invasion and dissemination. Emibetuzumab is a humanized IgG4 monoclonal antibody that binds to and inhibits ligand-dependent and ligand-independent activation of MET. In the first-in-human dose escalation study NCT0128756, emibetuzumab demonstrated favorable tolerability when administered up to 2000mg Q2W IV in unselected patients. The study was expanded to evaluate emibetuzumab in expansion cohorts for patients with tumors positive for MET expression. Methods: Patients with locally advanced or metastatic castration-resistant prostate cancer (CRPC) with bone metastasis, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), and hepatocellular carcinoma (HCC) received 2000 mg emibetuzumab Q2W IV on a 28-day cycle. RCC, NSCLC, and HCC patients were required to have measurable disease as defined by RECIST v1.1 and have MET positive tumors (≥50% of cells to be ≥2+ for MET expression) as determined by a MET IHC assay (Ventana). The objectives were to evaluate the safety and activity of emibetuzumab in patients with MET positive tumors. Additional objectives included pharmacokinetics (PK) and pharmacodynamics (PD). Results: A total of 62 patients received emibetuzumab across the 4 cohorts: CRPC n = 15, RCC n = 19, NSCLC n = 19,and HCC n = 9, with a median of prior systemic oncology therapies of 6, 3, 5, and 3, respectively. Common possibly related treatment-emergent adverse events included fatigue (29% all grades, 3% Gr3/4), nausea (13% all grades, no Gr3/4), edema of limbs (8% all grades, 2% Gr3/4), and anorexia (8%, no Gr3/4) and were similar among cohorts. No evidence of clinical activity was observed in CRPC patients. For RCC, NSCLC, and HCC patients with MET positive tumors, an overall disease control rate (DCR = partial response [PR] + stable disease [SD]) of 32% (15/47) was observed. In the individual cohorts, DCR was 26% (5/19) in RCC, 26% (5/19) in NSCLC, and 56% (5/9) in HCC. The median duration of disease stabilization in the 3 cohorts was: 4.2 months (range 1.6-24.6) in RCC, 3.9 months (range 2.5-6.4) in NSCLC, and 3.7 months (range 1.2-6.6) in HCC. One PR was observed in an HCC patient with MET amplification. After a single dose of 2000 mg emibetuzumab, PK parameters were similar among these cohorts and also comparable to patients treated at this dose during dose escalation. Conclusions: In cohorts enriched for tumor MET expression, limited single-agent activity of emibetuzumab was observed indicating that MET positivity by IHC (Ventana assay) at the cut-point employed here might not be a sufficient predictive biomarker to select patients receiving benefit from emibetuzumab monotherapy for the tumor types studied. Further evaluation of biomarkers/assays to identify patients who may benefit from treatment with emibetuzumab may be warranted. Citation Format: Michaela S. Banck, Rashmi Chugh, Ronald B. Natale, Alain Algazi, Bradley C. Carthon, Lee S. Rosen, Michael E. Menefee, Andrew Xiuxuan Zhu, Takami Sato, Brian Moser, P. Kellie Turner, Jay Tuttle, Xuejing Aimee Wang, Volker Wacheck, Frederick E. Millard. Phase 1 results of emibetuzumab (LY2875358), a bivalent MET antibody, in patients with advanced castration-resistant prostate cancer, and MET positive renal cell carcinoma, non-small cell lung cancer, and hepatocellular carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A55.

Abstract 544: Lung cancer classification using new immunohistochemical assay with anti-p40 (BC28) mouse monoclonal antibody: Comparison with the p40 Echelon assay and anti-p63 (4A4) antibody

Abstract Background: The precise differentiation of lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SCC) is essential for the determination of appropriate cancer therapy. Currently, the anti-p63 (4A4) antibody is the most frequently used marker for the lung SCC classification. A major limitation of this antibody is low specificity due to its reactivity in a substantial proportion of lung ADCs. The p63 antibody recognizes two p63 isoforms - 1) long TAp63 isoform and 2) a truncated variant designated as p40. In contrast to the anti-p63 antibody, the anti-p40 (BC28) antibody recognizes only the p40 isoform. The goal of this study was to compare a newly optimized IHC assay using the anti-p40 (BC28) antibody and OptiView IHC DAB Detection Kit with 1) the commercially available p40 Echelon assay, and with 2) an IHC assay using the anti-p63 (4A4) antibody in various lung tumors. Methods: Lung tumors from 271 patients were evaluated for p40 and p63 expression using IHC on VENTANA BenchMark XT platform with OptiView detection. The p40 expression was also evaluated by the commercially available anti-p40 (BC28) Echelon assay (Biocare Medical Inc.) using the manufacturer's recommended protocol. After the initial classification of these tumors by H&amp;E, anti-Napsin A (MRQ-60), anti-Cytokeratin 5/6 (D5/16B4) or anti-TTF-1 (SP141) antibodies were used for the evaluation of the discordant cases when H&amp;E and p40/p63 status did not correlate. Results: The anti-p40 and anti-p63 antibodies showed nuclear staining with no or minimal background. After resolving discordant cases, the new optimized Ventana assay using anti-p40 (BC28) antibody demonstrated superior sensitivity to the p40 Echelon assay in SCC classification. 92.9% of cases (52/56) showed p40 positive staining with the new p40 assay compared to 73.2% SCC cases (41/56) stained with p40 Echelon assay. In addition, the new p40 IHC assay demonstrated increased specificity compared to the anti-p63 antibody for ADC classification. 7.7% lung ADCs (13/169) were positive with anti-p63 antibody but only 3.0% (5/169) ADCs were positive with anti-p40 antibody. The new p40 assay correctly classified 96.0% SCC and ADC cases while 91.2% and 93.8% SCC and ADC case were correctly classified with p40 Echelon assay and anti-p63 antibody, respectively. All of the other lung tumors were negative for p40 and p63 except one bronchioloalveolar carcinoma case (1/14) and 6 adenosquamous carcinoma cases (6/13). Conclusion: In summary, the optimized p40 assay shows an improved sensitivity over the p40 Echelon assay, while both these p40 assays demonstrate a higher specificity compared to IHC assay using anti-p63 (4A4) antibody. Citation Format: Katerina Dvorak, Christian Roessler, John Palting, Akira Moh. Lung cancer classification using new immunohistochemical assay with anti-p40 (BC28) mouse monoclonal antibody: Comparison with the p40 Echelon assay and anti-p63 (4A4) antibody. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 544. doi:10.1158/1538-7445.AM2015-544

Comparison of evaluations of hormone receptors in breast carcinoma by image-analysis using three automated immunohistochemical stainings

The aim of this study was to compare the results of immunohistochemistry (IHC) assays evaluated by human examiners with the results evaluated by computerized image analysis, and to compare the computerized image analysis results among three automated IHC assays, namely the BioGenex, Dako and Ventana assays. All slides were semiquantitatively evaluated according to the Allred score and J-score by human examiners. The images were analyzed using MacSCOPE version 2.6 for Macintosh according to the H-score and the percentage of positive-stained nuclei per area of carcinoma cells (PP) irrespective of the intensity of the stained nuclei. The H-score for the estrogen receptor (ER) was significantly correlated with the Allred score (P<0.0001) and the PP for the ER was significantly correlated with the J-score (P<0.0001), suggesting that the image analysis used in the present study is a useful method for the evaluation of ER status. Several discrepancies were identified between the Allred score and H-score and between the PP and J-score due to the positive-stained cytoplasm area of carcinoma cells and/ or the positive-stained nuclei area of non-carcinoma cells, including benign epithelial cells, lymphocytes and stromal cells. Accordingly, advances in the algorithm of the digitized analyzing system is necessary.