Archival Biopsy Samples Research Articles

Long-term outcome and antitumor immune activation response in prostate cancer treated with low-dose-rate brachytherapy.

To evaluate the long-term clinical outcomes of iodine-125 low dose-rate brachytherapy (LDR-BT)-based treatment approaches for ≤ cT3 prostate cancer (PC) patients in China, as well as the effects on the PC immune microenvironment. Data was retrospectively collected from 237 patients with ≤ cT3 PC who were treated with radical prostatectomy (RP) or LDR-BT alone or in combination with androgen deprivation therapy (ADT), and biochemical progression-free survival (bPFS), prostate cancer-specific survival (PCSS) and overall survival (OS) rates were compared. In 63 cases, PC patients received RP after biopsy, received at least 6 months of ADT before RP, or received LDR-BT and deferred limited transurethral resection of the prostate (TURP). Immunohistological analyses and expression comparisons of programmed death-ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs, expressing CD3, CD4, CD8, and PD-1) on tissue sections from archival prostate biopsy samples with corresponding TURP or RP history were performed by paired t test. The 8-year bPFS, PCSS, and OS rates for LDR-BT and RP were 53.4% and 63.6%, 84.9% and 86.8%, and 63.8% and 70.2%, respectively, although these differences were not statistically significant. PD-L1 was expressed in 35 of 63 cases. The average infiltration scores of TILs (expressing CD3, CD4, and CD8) were 3.6 (1-5), 2.90 (1-5), and 2.46 (1-5), respectively. PD-1 + T cells were seen in 55.6% of cases, with an average score of 0.89 (range: 0-3). In TURP tissue samples from 23 patients, CD3+, CD4+, and CD8 + T cells increased significantly. PD-1 + T cells exhibited a moderate increase, with conversion to positive PD-1 expression in T cells observed in 13 out of 14 cases. The PD-L1 expression score of PC cells was significantly elevated, with conversion to positive in 8 of 9 cases. LDR-BT monotherapy and combination therapy with external beam radiotherapy (EBRT) and ADT are suitable treatment approaches for low-risk and intermediate- or high-risk PC, respectively. Most TILs in PC are not tumor antigen-specific T-cells. LDR-BT can stimulate anti-tumor immunity during a narrow time window and should be combined with immunotherapy as an auxiliary therapy.

An exploratory study investigating the impact of the bladder tumor microbiome on Bacillus Calmette Guerin (BCG) response in non-muscle invasive bladder cancer

PurposeIntravesical Bacillus Calmette-Guerin (BCG) is standard of care for intermediate- and high-risk non-muscle invasive bladder cancer (NMIBC). The effect of the bladder microbiome on response to BCG is unclear. We sought to characterize the microbiome of bladder tumors in BCG-responders and non-responders and identify potential mechanisms that drive treatment response. Materials and methodsPatients with archival pre-treatment biopsy samples (2012-2018) were identified retrospectively. Prospectively, urine and fresh tumor samples were collected from individuals with high-risk NMIBC (2020-2023). BCG response was defined as tumor-free 2 years from induction therapy. Extracted DNA was sequenced for 16S rRNA and shotgun metagenomics. Primary outcomes were species richness (α–diversity) and microbial composition (β-diversity). Paired t-tests were performed for α–diversity (Observed species/Margalef). Statistical analysis for β-diversity (weighted and unweighted UniFrac distances, weighted Bray-Curtis dissimilarity) were conducted through Permanova, with 999 permutations. ResultsMicrobial species richness (P < 0.001) and composition (P = 0.001) differed between BCG responders and non-responders. Lactobacillus spp. were significantly enriched in BCG-responders. Shotgun metagenomics identified possible mechanistic pathways such as assimilatory sulfate reduction. ConclusionA compositional difference exists in the tumor microbiome of BCG responders and non-responders with Lactobacillus having increased abundance in BCG responders.

Myofibroblast and pro-fibrotic cytokines in fibrosis of IgG4-related disease (IgG4-RD) patients from South Asia: preliminary data.

Fibrosis is a typical pathological characteristic in IgG4-RD patients and often irreversible. There exists a lack of suitable markers for detection of earlier onset of fibrosis in various organs in IgG4-RD patients. Hence, this study aims at analysing ambispectively the myofibroblasts and the pro-fibrotic cytokines, IFN gamma and IL-33 involved in IgG4-RD associated fibrosis in South Asian patients. Archived biopsy samples of definite/probable/possible cases of IgG4-RD, classified according to diagnostic criteria, taken from patients who attended the OPD and IPD of our tertiary care centre during January 2015-January 2020 were chosen for this study.The paraffin sections were examined qualitatively for fibrosis and the excessive collagen deposition by Hematoxylin & Eosin and Masson's Trichrome staining. Also, the presence of alpha-Smooth muscle actin (α-SMA) expressing myofibroblasts and the involvement of pro-fibrotic cytokines (IFN-gamma, IL-33) were assessed by Immunohistochemistry and scored semi-quantitatively (+mild, ++moderate, +++ severe). Serum IL-33 levels were analysed by indirect Elisa (R & D Systems). Myofibroblasts were present in 10/12 biopsy samples, in moderate levels in 4 (33%) and very high levels (+++) in 3 (25%) of the patients. IFN-gamma was expressed at low levels in 6 (50%) and absent in 6 (50%). All patients showed IL-33 expression with very high levels in tissue (6, 50%), as well as in serum samples. The findings of this study reinforce the role of myofibroblasts and profibrotic cytokines like IL-33 in fibrosis of Ig4-RD patients, pointing to their potential as earlier predictive markers of onset and extent of fibrosis.

Prevalence of Clarithromycin-Resistant Helicobacter pylori Strains in Zambia: A Sub-Saharan African Country

Introduction: Helicobacter pylori (H. pylori) is one of the most important infections globally, affecting more than 50% of the human population. Clarithromycin (CLA)-containing regimens are recommended for empirical eradication of H. pylori in populations with less than 15% resistance. The aim of this study was to estimate the prevalence of CLA resistance in samples collected from Zambian patients to determine if CLA is suitable for first-line H. pylori empirical treatment. Methodology: We used archival biopsy samples collected from dyspeptic patients undergoing endoscopy. The samples had been snap-frozen immediately after collection and stored at −80°C. We performed multiplex real-time PCR using Bosphore Helicobacter pylori Genotyping Kits v1, Istanbul, Turkey, to determine the presence of wild-type H. pylori and three mutations, A2142G, A2142C, and A2143G, of domain V in 23s rRNA gene. Results: We tested 259 gastric biopsy samples from patients with dyspepsia, of which 136 (53%) were from females. The median age was 48 years (IQR 40–61 years). Endoscopically, most of the patients, 164 (63%), had a normal gastric mucosa. CLA resistance was found in 48 (28%) samples, with A2142G mutation in 23 (13%), A2143G mutation in 32 (18%), and double mutations A2142C and A2143G in 6 (3%). Conclusions: The presence of significant levels of CLA resistance in Zambia suggests that it should not be used as first-line empirical treatment for H. pylori infection. However, with a limitation of suitable alternatives, there is an urgent need to formulate new treatment approaches.

Expression profiles of glucocorticoid-inducible proteins in human papilloma virus-related oropharyngeal squamous cell carcinoma.

Human papillomavirus virus-related oropharyngeal squamous cell carcinoma (HPV-OPSCC) comprises a significant portion of head and neck cancers. Several glucocorticoid-inducible proteins play important roles in pathogenesis of some cancers but their status and roles in HPV-OPSCC remain elusive; these include the glucocorticoid-induced leucine zipper (GILZ), Annexin-A1 and serum glucocorticoid-regulated kinase-1 (SGK-1). We determined expression profiles of these proteins, using immunohistochemistry, in archived biopsy samples of patients diagnosed with HPV-OPSCC; samples of non-cancer oral lesions (e.g., hyperkeratosis) were used as controls. GILZ staining was primarily confined to nuclei of all tissues but, in HPV-OPSCC specimens, neoplastic cells exhibiting mitosis displayed prominent cytoplasmic GILZ expression. On the other hand, nuclear, cytoplasmic and membranous Annexin-A1 staining was observed in suprabasal cell layers of control specimens. A noted feature of the HPV-OPSCC specimens was few clusters of matured and differentiated nonbasaloid cells that showed prominent nuclear and cytoplasmic Annexin-A1 staining while the remainder of the tumor mass was devoid of staining. Cytoplasmic and nuclear staining for SGK-1 was prominent for control than PV-OPSCC specimens while staining for phosphorylated SGK-1 (pSGK-1; active) was prominent for cell membrane and cytoplasm of control specimens but HPV-OPSCC specimens showed mild and patchy nuclear and cytoplasmic staining. Semi-quantitative analysis of GILZ immunostaining indicated increased staining area but similar normalized staining for HPV-OPSCC compared to control specimens. By contrast, staining area and normalized staining were reduced for other proteins in HPV-OPSCC than control specimens. Our collective observations suggest differential cellular localization and expression of glucocorticoid-inducible proteins in HPV-OPSCC suggestive of different functional roles in pathogenesis of this condition.

The contribution of histopathology to the diagnosis of tuberculosis. Lessons from archival biopsy samples.

Histopathological analysis of tissue samples is an ancillary complementary diagnostic tool in tuberculosis (TB) with variable sensitivity and specificity according to different clinical settings. We evaluated the spectrum of histological findings, their diagnostic sensitivity, diagnostic utility, and requests over time in a sample of archival biopsies. Analysis of biopsies of confirmed TB cases between years 2011-2019 at a reference hospital in Chile. The series included patients with a histological study for TB confirmed by culture (88.9%) or PCR (11.1%). In total, 34 samples were available for analysis, most of them of extrapulmonary origin (82.4%). Biopsies were taken before the start of treatment in 26 cases (76.5%) or after the start-end of treatment for different reasons in 8 cases (23.5%). Restricting the analysis to the group with pretreatment biopsies, the prevalence/diagnostic sensitivity of granulomas was 93.3%, 69.2% for caseous necrosis, 26.9% for granulomas with caseous necrosis without acid-fast bacilli (AFB), and 46.2% for AFB in any histological context. A histological score was constructed to evaluate the homogeneity of lesions, observing that 76.9% had at least four of the six components of the score. The request for biopsies was maintained over time despite the increase in the use of molecular techniques. The presence of AFB contributed to the diagnosis before microbiological results in 23.1% of the cases. Histological study continues to contribute to the diagnosis of TB, especially in extrapulmonary forms.

Hyperactivation of the JAK2/STAT5 Signaling Pathway and Evaluation of Baricitinib Treatment Among Patients With Eosinophilic Cellulitis

The pathogenesis of eosinophilic cellulitis (EC) is poorly understood, limiting available treatment options. The current treatment paradigm focuses on delayed type 2 hypersensitivity reaction to various triggers. To gain further insight into the nature of EC inflammation and into the cellular signal transduction pathways that are activated in the context of EC. This case series was conducted in Lyon, France, from January 2018 to December 2021. Analysis of archival skin biopsy samples from patients with EC and from healthy control participants was performed using histology, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) immunohistochemistry, and gene profiling. Data analysis was conducted between January 2020 and January 2022. Pruritus (visual analog score), percentage of body surface area with lesional skin, and RNA transcripts of inflammatory biomarkers from the skin (threshold cycle) were assessed in 1 index patient with refractory EC who received oral JAK1/JAK2 inhibitor baricitinib (4 mg/d). This study included samples from 14 patients with EC (7 men and 7 women) and 8 healthy control participants (4 men and 4 women). The mean (SD) age of patients was 52 (20) years. Marked type 2 inflammation (chemokines CCL17, CCL18, and CCL26 and interleukin 13) with preferential activation of the JAK1/JAK2-STAT5 pathways in EC lesions was observed. In the 1 index patient with refractory EC, complete clinical remission of skin lesions was observed after 1 month of treatment with baricitinib. These findings suggest that EC is a type 2 inflammatory disease with preferential activation of the JAK1/JAK2-STAT5 pathways. In addition, these results suggest the potential of treatment approaches targeting JAK1/JAK2 for patients with EC.

Characterization of IGF2R Molecular Expression in Canine Osteosarcoma as Part of a Novel Comparative Oncology Approach.

Progress in prognostic factors, treatments, and outcome for both canine and human osteosarcoma (OS) has been minimal over the last three decades. Surface overexpression of the cation independent mannose-6-phosphate/insulin-like growth factor receptor type 2 (IGF2R) has been proven to occur in human OS cells. Subsequently, radioimmunotherapy (RIT) targeting IGF2R has demonstrated promising preliminary results. The main aims of this study were to investigate the expression of IGF2R in spontaneously occurring canine OS cells using immunohistochemistry (IHC) on archived biopsy samples and to assess its prognostic significance. Thirty-four dogs were included in the study. All cases showed that 80-100% of OS cells stained positive for IGF2R. IGF2R overexpression alone was not shown to have prognostic significance using both visual and quantitative methods of IHC staining intensity. This study has established for the first time the consistent expression of IGF2R in spontaneously occurring canine OS. This comparative oncology approach will allow further investigation into RIT as a novel treatment modality; first in canines and then in humans with OS. In addition, further studies should be performed to assess the true prognostic significance of IGF2R overexpression.

Considerations on the identification and management of metastatic prostate cancer patients with DNA repair gene alterations in the Canadian context.

Olaparib is the first Health Canada-approved agent in metastatic prostate cancer to use a companion diagnostic to identify alterations in BRCA1, BRCA2, or ATM. As olaparib is introduced, clinicians must learn to access and interpret germline and somatic next-generation sequencing (NGS) results, and how to manage affected patients who appear to have distinct clinical features. The traditional model of referring patients to a hereditary cancer clinic (HCC) for germline testing is likely impractical in this disease, as the metastatic prostate cancer patient population would be overwhelming. Alternate approaches to this are clinician-ordered genetic testing (so-called “mainstreaming”), out-of-pocket payment for third-party private company genetic testing, or germline testing done in conjunction with somatic testing, particularly cell free circulating tumor DNA (ctDNA). Germline testing alone is not sufficient for identifying Olaparib-eligible patients, as less than half of BRCA1, BRCA2, or ATM alterations are germline in origin, but it is critically important to identify family members who are carriers so that risk-reduction measures can be undertaken. Somatic testing is not widely available in Canada, but some patients can access it through research protocols or by paying out-of-pocket. Somatic testing can be performed on archival or fresh solid tissue biopsy samples, or through whole blood samples to access plasma-derived circulating tumor DNA (ctDNA). Both testing approaches have relative advantages and disadvantages, but neither may be informative in all patients and, therefore, ideal somatic NGS pathways should provide options for both tissue and ctDNA testing. We advocate that clinicians begin discussions with their provincial lab formularies, HCC, and molecular pathology labs to highlight the importance of germline and somatic testing in this population and identify pathways for patient access. While olaparib has approval for use in BRCA1, BRCA2, and ATM-altered mCRPC, emerging evidence suggests that PARP inhibitors have variable activity in these three genes, with BRCA2 alterations appearing to be the most responsive. Retrospective and prospective series have reported varying outcomes to standard of care therapies, such as ARATs and taxane-based chemotherapy, in metastatic castration-resistant prostate cancer (mCRPC) patients with DNA damage repair (DDR) gene alterations, such as BRCA2. In the absence of high-level evidence showing a lack of benefit, we believe this patient population should still be considered for these treatments. In addition, platinum-based chemotherapy appears to have activity in DDR gene-altered mCRPC and should be considered another option when access to olaparib is not possible. At present, there is no evidence to support an optimal treatment sequence in this patient population, therefore, physician and patient preferences will need to be taken into consideration when selecting therapies. As olaparib and other PARP inhibitors are tested in different disease states and in combination with other therapies, we will likely see a more refined approach to use of these agents and management of this new biomarker-defined patient population.

Molecular and Genetic Characterization of Tumor Samples from Patients with Relapsed or Refractory Follicular Lymphoma Identifies Factors Influencing Response to Tazemetostat

Molecular and Genetic Characterization of Tumor Samples from Patients with Relapsed or Refractory Follicular Lymphoma Identifies Factors Influencing Response to Tazemetostat

P60.01 Investigation of Aurora Kinase A as a Potential Biomarker of Radiation in Non-Small Cell Lung Cancer (NSCLC)

Aurora Kinases belong to a family of serine/threonine kinases with three known subtypes: AURKA, Aurora B (AURKB) and Aurora C (AURKC) (Tao et al., 2008). Their overexpression is linked to tumorigenesis, chemotherapy, and radiation resistance. AURKA inhibition leading to enhanced radiosensitivity has been demonstrated in our laboratory. There is interest in determining whether the increased expression of AURKA is linked to patient survival. The purpose of this study is to examine the correlation between increased AURKA expression in patient biopsies and survival in patients with NSCLC. One hundred and one patients were recruited to a prospective study where the patient was offered radical and high dose palliative radiation for NSCLC—65% of patients presented with stage III and IV advanced disease. Archived biopsy samples collected before radiotherapy were stained for AURKA expression using immunohistochemistry. The tumour cells on each slide were counted and categorised as negative, borderline, weak or definite staining. The percentage ratio of staining on each slide between each category was recorded. The combined percentage of weak and definite categories in each slide were added and classified as a “positive stain” with borderline and negative categories a “negative stain”. The mean of the combinations of weak and definite stains in all slides was calculated (12.92%). Slides with a combined total percentage of weak and definite staining greater than 12.92% would be defined as AURKA positive. The mean staining of weak and definite slides was correlated with overall and progression-free survival. The median overall survival for patients entering the study was 266 days (8.8 months), 95% Confidence Interval (CI), 203 - 374 days). Median progression-free survival was 171 days (5.7 months (95% CI 116 - 279 days). There was no statistical difference in overall and progression-free survival between AURKA positive and AURKA negative biopsies. (figure1). The expression of AURKA did not result in significant differences in overall or progression-free survival.

Detection of Endogenous DNA Double-strand Breaks in Oral Squamous Epithelial Lesions by P53-binding Protein 1.

P53-binding protein 1 (53BP1) is one of the DNA damage response (DDR) molecules. This study aimed to assess 53BP1 expression by immunofluorescence (IF) as a biomarker to differentiate between oral squamous epithelial lesions (OSELs). We analyzed 129 archival oral biopsy samples, including 18 benign squamous lesions (BSLs), 37 low-grade dysplasias (LGDs), 22 high-grade dysplasias (HGDs), and 52 oral squamous cell carcinomas (OSCCs). 53BP1 and Ki-67 expressions were examined by double IF to assess the type of 53BP1 expression. We found that OSCC exhibited several 53BP1 nuclear foci, particularly high-DNA damage response (HDDR) and large focus (LF)-type, suggesting the presence of endogenous DNA double-strand breaks in the cancer genome, which could disrupt DDR and induce genomic injury. We also found a difference in 53BP1 expression between LGD and HGD, but not between BSL and LGD. Among the Ki-67-positive cells, HDDR- and LF-type expressions were higher in OSELs of higher grades. 53BP1 expression can be a valuable biomarker for OSELs to help estimate the grade of oral epithelial dysplasia.

Using the tumor microenvironment to identify predictors of immunotoxicity to checkpoint inhibitors.

2545 Background: While Immune checkpoint inhibitors (ICI) have revolutionized the field of oncology, the benefits have come at the cost of serious side effects known as immune-related adverse events (irAEs). Approaches that can predict patients’ susceptibility to irAEs are key to their early detection and management. In the present study, we investigate the association between irAEs reported during ICI therapy across multiple cancer types and markers of tumor immune response. Our primary objective is to explore potential biomarkers for assessing patients’ risk of irAEs. Methods: 472 patients were evaluated who had tumor immune profiling performed paraffin embedded formalin fixed archival tumor biopsy samples using Omniseq Immune Report Card (IRC) and subsequently underwent ICI therapy. The IRC consisted of enumeration of tumor infiltrating lymphocytes (TILs) by immunohistochemistry (IHC) and TIL-associated genes by RNA-Seq, PD-L1 expression by IHC, and tumor mutational burden (TMB) by DNA-Seq. irAE type and grade were determined based on retrospective chart review. Fisher’s exact test was used to determined statistically significant associations between immune markers and irAE development. Results: Patients with lung (55%), ovarian (9%), and melanoma (5%) cancers constituted the majority of the cases. The median age of patients was 61, with 56% being female and 44% male. Most patients underwent treatment with (94%). irAEs developed in 36% of patients, with 2% of patients developing high-grade irAEs (Grade 3 or 4). Skin (11%), thyroid (10%), and GI (9%), were the most commonly affected organ systems. Increased TILs were associated with increased risk for any irAE (p = 0.04). A stronger association was noted in patients who underwent anti-PD-1/L1 monotherapy (p = 0.01) and/or in cases of lung cancer (p = 0.01). Interestingly, subanalyses by gender showed a statistically significant correlation between increased TILs and risk for any irAE in males (p = 0.006) but not in females (p = 0.63). High PD-L1 (defined as &gt; 70% by IHC) was also significantly associated with increased risk for any irAE (p = 0.03). Subanalyses by gender and age again showed a similar association in females (p = 0.0002) and/or patients &lt; 65 years (p = 0.04). high TMB and any irAE in female patients (p = 0.01) and in breast cancer cases (p = 0.03). On multivariate analysis, TILs by IHC appeared to be the strongest predictor of irAEs (p = 0.03). Conclusions: The tumor immune microenvironment (TME) has been shown to influence response to ICI, yet its association with irAEs has not been well studied. Our analysis sheds light on potential TME predictors for irAE in patients receiving ICI therapy. Further studies are needed to deepen our understanding of immune toxicity and to develop tools for identifying patients who are at risk.

Immunohistochemical evaluation of potential molecular targets of desmoid-type fibromatosis

Desmoid-type fibromatosis is locally aggressive tumor rare in general population, although commonly present in patients with familial adenomatous polyposis, significantly contributing to the morbidity and mortality of patients. To optimize and individualize the management of patients it is necessary to better understand the biology of these tumors. Immunohistochemical analysis of β-catenin, VEGF, hormone receptors ERβ, ERα and PR, COX-2, APC protein, EGFR, c-kit (CD117), bcl-2 and HER2 expression, potential therapeutic targets, was carried out on 15 archival biopsy samples together with APC gene mutational screening. β-catenin expression was found in all samples, with over 73% showing high range positivity, however with no prognostic significance. Non-specific cytoplasmic localization of β-catenin was observed FAP-associated cases lacking CTNNB1 mutations. Hormone receptor status demonstrated expression of ERβ in 93% of lesions, without detectable ERα or PR. Distinct COX-2 expression of variable intensity was present in all but one desmoid-type fibromatosis case. All lesions demonstrated intense VEGF positivity. Immunoreactivity for the APC protein was found only in 4 cases associated with FAP. No EGFR, HER2, bcl-2 or c-kit expression was detected in any sample. Expression of β-catenin, VEGF, ERβ, COX-2 in high number of cases suggests a potential as future therapeutic targets in desmoid-type fibromatosis.

350 - A pilot transcriptomic analysis of archival prostate biopsy samples and response to radical radiotherapy

350 - A pilot transcriptomic analysis of archival prostate biopsy samples and response to radical radiotherapy

Abstract 4024: Phase 1/2a LYM1002 study of ibrutinib (ibr) + nivolumab (nivo): Exome and gene expression profiling (GEP) analyses by histology and responder status

Abstract A phase 1/2a study (LYM1002 [EudraCT 2014-005191-28]) of ibr (560 mg once daily) + nivo (3 mg/kg on a 14-day cycle) demonstrated acceptable safety and promising efficacy vs single-agent ibr in Richter’s transformation (RT), follicular lymphoma (FL), and diffuse large B-cell lymphoma (DLBCL). We examined potential biomarkers of treatment (tx) response using archived biopsy samples. GEP was used for DLBCL subtyping and to assess proportions of 22 distinct immune cells. Exome data were generated from 72 formalin-fixed paraffin-embedded samples, and sequencing analysis was used to identify mutations in genes of interest and assess somatic mutation burden. The correlations of immune cell proportions and gene variants were evaluated by investigator-assessed responses in each histology and by ongoing responses in DLBCL patients (pts; progression-free survival [PFS] &amp;gt; 24 months, n = 7 vs not, n = 20). In pts with available GEP and response data, overall response rates were 29.6% (8/27) for DLBCL, 43.5% (10/23) for FL and 81.3% (13/16) for RT. Proportions of CD8 and follicular helper T cells, M1 macrophages, and resting dendritic cells were higher in DLBCL responders vs nonresponders, while the proportion of regulatory T cells was decreased. These subsets did not differ by response in FL although an increase of CD4 memory resting T-cells was noted in responders. The trend toward increased follicular helper T cell and resting dendritic cell proportions in DLBCL pts was also associated with longer survival (PFS &amp;gt; 24 months) vs not. Gene variant data and responder status were available for 26 pts with DLBCL, 26 with FL, and 17 with RT. Comparison between responders and nonresponders showed that DLBCL pts with RNF213 (4/10 [40.0%] vs 1/16 [6.2%]) and KLHL14 (3/10 [30.0%] vs 0/16) mutations were more likely to respond to ibr + nivo. Conversely, nonresponders were associated with variants in EBF1, ADAMTS20, AKAP9, SOCS1, TP53, and genes in BCR pathways such as TNFRSF14, MYD88, and NFKB1B. BCL2 mutation in FL (9/12 [75.0%] vs 4/14 [28.6%]) and ROS1 mutation in RT (0/13 vs 2/4 [50.0%]) were associated with response; both are involved in the NF-kB pathway. In DLBCL, the most frequent gene mutations were RNF213, NBPF1, and BCL2 in pts who had PFS &amp;gt; 24 months (3/7 [42.9%] each), and KMT2D (8/20 [40.0%]) and CSMD3 (8/20 [40.0%]) in pts who did not. Somatic mutation burden was lower in responders vs nonresponders, especially in germinal center B-cell-DLBCL, and in DLBCL pts with PFS &amp;gt; 24 months vs not. In conclusion, we report gene variations among DLBCL, FL, and RT pts associated with response or durable PFS with ibr + nivo. While ibr inhibits Bruton’s tyrosine kinase-dependent pathways, we identify alternative gene pathway variants that may impact tx outcomes. Immune cell infiltration into the microenvironment relates to differential tx response with this immune combination and is histology dependent. Citation Format: Brendan Hodkinson, Michael Schaffer, Joshua Brody, Wojciech Jurczak, Cecilia Carpio, Dina Ben-Yehuda, Irit Avivi, Rao Saleem, Muhit Özcan, John Alvarez, Rob Ceulemans, Nele Fourneau, Sriram Balasubramanian, Anas Younes. Phase 1/2a LYM1002 study of ibrutinib (ibr) + nivolumab (nivo): Exome and gene expression profiling (GEP) analyses by histology and responder status [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4024.

Morphological, immunohistochemical and molecular features of inflammatory bowel disease associated colorectal carcinoma and associated mucosal lesions – Single institution experience

BackgroundPatients with inflammatory bowel disease (IBD) – ulcerative colitis (UC) and Crohn’s disease (CD) have an elevated risk of developing colorectal carcinoma (CRC). Major risk factor in IBD patients is the continuous chronic inflammation leading to development of dysplasia and carcinoma. Nevertheless, other types of non-conventional but suspicious mucosal changes serrated change/dysplasia, NOS and villous hypermucinous change, have also been reported in IBD patients. Preneoplastic potential of these lesions is still not well elucidated. AimsThe aim of this study was identification of IBD-associated CRCs focusing on finding related precursor lesions in the surgical specimen or in archival biopsy samples followed by a detailed morphological, immunohistochemical and molecular evaluation. For the purpose of the study the mucosal lesions were divided into conventional IBD-associated dysplasia and non-conventional lesions that were merged under a provisory term of putative preneoplastic lesions (PPL). MethodsA total of 309 consecutive IBD colectomy specimens diagnosed during a 10-year period were reviewed. Detailed morphological evaluation, immunohistochemical analysis of mismatch repair (MMR) proteins, p53 and O6-methylguanine DNA methyltransferase (MGMT) expression and molecular analysis for KRAS, NRAS and BRAF gene mutation were performed in the retrieved CRC cases as well as in the detected dysplasia and PPLs of these patients. ResultsWe identified 11 cases of morphologically heterogenous IBD-associated CRCs, occurring in 5 males and 6 females, aged 26–79 years (mean 44 years). A total of 22 mucosal lesions were revealed in 8 CRC patients comprising conventional IBD-associated dysplasia (4 lesions), PPLs as serrated change/dysplasia NOS (11 lesions), villous hypermucinous change (5 lesions), and two true serrated lesions (one sessile serrated adenoma and one traditional serrated adenoma). More than one type of lesion was found in 6 patients. Seven CRC cases harbored mutation of KRAS/NRAS and one case of BRAF. Two patients with KRAS-mutated CRC showed the same mutation in PPL in the same specimen (one serrated change NOS and one TSA with high-grade dysplasia). Similarly, one BRAF-mutated carcinoma case presented the same mutation in serrated change/dysplasia, NOS in the same specimen. Of the CRCs, two showed deficient MMR system profile, six presented with loss of MGMT expression, and six showed aberrant p53 expression. PPLs showed deficient MGMT expression (14 cases) and aberrant p53 (10 cases) as well. ConclusionIBD-associated CRCs are very heterogeneous entities. Besides conventional IBD-related dysplasia, other types of mucosal lesions may be associated with long lasting IBD and CRC e.g. villous hypermucinous change and serrated change/dysplasia, NOS. Since these lesions share certain genetic or immunohistochemical changes with the related CRC, a suspicion is raised that these lesions may also have preneoplastic potential. Awareness of these changes is necessary to prevent their missing and under-reporting, and further studies of these lesions should be carried out.

Detection of Leishmania spp. Infection by Immunohistochemistry in Archived Biopsy Samples from Dogs with Colitis in an Area Endemic for Leishmaniosis

Previous studies have demonstrated the presence of Leishmania infantum amastigotes in the colonic mucosa of seropositive sick dogs. However, there are no studies that have investigated the presence of L. infantum infection in dogs diagnosed with inflammatory bowel disease (IBD). The aims of this study were: (1) to investigate retrospectively the presence of Leishmania spp. antigen by immunohistochemistry (IHC) in biopsy samples taken from the colon of dogs with IBD in an area endemic for leishmaniosis, and (2) to describe the main histopathological findings in these cases. Clinicopathological data and histopathological results were reviewed from 106 cases of canine colitis. IHC to detect Leishmania spp. antigen had been performed at the time of diagnosis in 13 cases and we performed IHC in 56 more cases. Five of the 69 cases (7.2%) were positive for Leishmania spp. antigen by IHC. Two positive biopsy samples had histiocytic inflammation and three had lymphoplasmacytic inflammation. The number of amastigotes was variable and independent of the type and grade of inflammatory infiltrate. The results suggest that Leishmania spp. infection is associated with chronic colitis in areas endemic for the infection. Therefore, Leishmania IHC should be used routinely as a diagnostic tool when evaluating colonic biopsy samples from dogs in endemic areas, to exclude or confirm an infection by this parasite in dogs with chronic colitis.

Abstract 3807: ATM protein loss and clinical outcomes with platinum chemotherapy in patients with advanced solid tumors

Abstract Background Loss of ataxia telangiectasia mutated (ATM), a key protein regulating DNA damage repair signaling, appears to sensitize tumors to platinum chemotherapy in preclinical studies. In this study, the incidence of ATM loss in patients with advanced solid tumors and clinical outcomes with platinum chemotherapy was analyzed. Methods Archival tumor and biopsy samples of primary or metastatic sites of patients treated in a phase I trial unit were retrieved and ATM immunohistochemistry (IHC), as well as targeted next generation sequencing (NGS) was performed. Analytic validation and assay optimization of rabbit monoclonal antibody [Y170] to ATM (Abcam ab32420) was undertaken using known positive (VCaP xenograft material and GM14680 cell pellet) and negative (GM01526 cell pellet) controls. IHC slides were assessed by a trained pathologist for nuclear staining intensity of ATM and semi-quantitatively scored. ATM loss was defined as a nuclear H score of ≤10. Clinical data were collected retrospectively from case records. Duration on platinum therapy was defined as time from start of first platinum therapy to time to subsequent therapy (adjuvant platinum excluded). Results Overall, 679 samples of 587 patients were tested for ATM IHC, of which 517 samples had NGS performed; 5% of patients (n = 31) had ATM IHC loss, and 5% (n = 27) had somatic ATM mutations detected by NGS (Table 1). In 70 matched primary/metastatic or different metastatic sites, concordance of ATM IHC loss occurred in 99% (n = 69; 7 with ATM IHC loss) of samples. Of the colorectal cancer cohort (n = 223), duration on platinum therapy was significantly longer for the ATM loss group (11 vs 8 months, HR: 0.57, 95% CI: 0.35 to 0.93, p = 0.04). Discussion Loss of ATM expression was detected among 5% of this cohort of advanced solid cancers, primarily in breast and gastrointestinal tumors. Sensitivity to platinum therapy is significantly higher in ATM loss colorectal cancer. Further prospective studies with larger cohorts are required to validate these findings. ATM IHC and ATM mutation by NGS by tumor groupTumor typesTotalATM IHC loss (%)ATM mutation (%)Concomitant ATM loss and ATM mutationConcomitant TP53 mutation with ATM IHC loss or mutationTotalMisense nFrameshift nTruncating n(as % of those with ATM IHC loss)(as % of those with ATM IHC loss/mutation)Colorectal22316(7)9(4)544 (25)10 (48)Gynaecological1051(1)7(7)4125 (63)Thoracic801(1)3(4)211 (100)2 (67)Breast448(18)4(9)223 (38)4 (44)Upper GI372(5)1(3)12 (67)Hepatobiliary221(5)1(5)11 (50)Others762(3)2(3)21 (50)Total58731(5)27(5)14 (52)3 (11)10 (37)9 (29)24 (49) Citation Format: Raghav Sundar, Susana Miranda, Suzanne Carreira, Maxime Chénard-Poirier, Daniel Nava Rodrigues, Ines Figueiredo, Claudia Bertan, Wei Yuan, Desamparados Roda Perez, Ana Ferreira, Nina Tunariu, Joaquin Mateo, Johann de Bono. ATM protein loss and clinical outcomes with platinum chemotherapy in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3807. doi:10.1158/1538-7445.AM2017-3807

Characterization of folate receptor alpha (FRα) expression in archival tumor and biopsy samples in a phase I study of mirvetuximab soravtansine, a FRα-targeting antibody-drug conjugate (ADC), in relapsed epithelial ovarian cancer patients

Characterization of folate receptor alpha (FRα) expression in archival tumor and biopsy samples in a phase I study of mirvetuximab soravtansine, a FRα-targeting antibody-drug conjugate (ADC), in relapsed epithelial ovarian cancer patients