Positive IHC Research Articles

7510 Use Of Tumor Markers And Surgery In The Management Of Medullary Thyroid Cancer During Pregnancy

Abstract Disclosure: M. Garver: None. C. Vaz: None. Introduction: Thyroid cancer is the second most diagnosed cancer during pregnancy, predominantly differentiated thyroid malignancies. [1] MTC during pregnancy is rare and challenging to manage due to its aggressive nature. We describe the successful diagnosis and management of MTC during pregnancy. Clinical Case: A 28 yo woman presented with a rapidly growing neck lump for 2 months with an associated unintentional 10lb weight loss and without compressive symptoms. She had no history of childhood radiation exposure or family history of thyroid cancer. Physical exam revealed a hard L lobe thyroid nodule without palpable lymphadenopathy. The patient was 5 weeks pregnant at the time. A neck US revealed a 4.2x2.7x2.0 cm L solid isoechoic thyroid nodule with punctate echogenic foci and microcalcifications. The nodule was classified as TIRADS 4 and ATA high suspicion. FNA noted Bethesda IV with positive IHC stains for chromogranin and calcitonin. Afirma MTC classifier was positive, confirming diagnosis of MTC. At 7 weeks gestation, calcitonin was markedly elevated at 3508 pg/mL (n <5 pg/mL), CEA 29.5 ng/mL (n <2.5 ng/mL) and calcium 10.3mg/dL (8.6-10.2mg/dL). Plasma normetanephrines were elevated to176 pg/mL (n <148 pg/mL) with normal metanephrines 28 pg/mL (n <57 pg/mL) and normal 24-hour urine metanephrines. CT neck revealed 3.2x2.8cm L thyroid nodule without cervical lymphadenopathy. Due to pregnancy status, additional imaging to assess for metastatic disease was deferred until after delivery. Genetic testing did not identify mutations within the thyroid cancer panel including APC, CHEK2, DICER1, MEN1, PRKAR1A, PTEN, RET, SDHB, SDHD, and TP53. The patient underwent total thyroidectomy with neck dissection at 19 weeks gestation without complication. Two weeks postoperative Calcitonin was 2 pg/mL(n <5 pg/mL) and CEA was undetectable. Conclusions: The effect of pregnancy on MTC is not well studied because of low incidence. Guidelines on the timing of surgery for MTC diagnosed during pregnancy are lacking. While evidence confirms that surgery can be safely postponed until after delivery for low risk differentiated thyroid malignancies, there is no consensus on timing of surgery for MTC. Given the aggressive nature of MTC, along with marked elevation of calcitonin and CEA in this case, surgery was performed in the 2nd trimester with excellent outcome. Data is conflicting on accuracy of calcitonin and CEA during pregnancy, with some reports suggesting falsely high levels due to pregnancy. The sharp decline in calcitonin and CEA 2 weeks postoperatively suggested these were truly elevated due to MTC and unaffected by pregnant status. We suggest that calcitonin and CEA be followed similar to non-pregnant cases with MTC. Resources: 1.Khaled, H. M., Lahloubi, N. A., & Rashad, N. (2016). A review on thyroid cancer during pregnancy: Multitasking is required. Journal of Advanced Research, 7(4), 565–570. Presentation: 6/2/2024

Simultaneous p53 and p16 Immunostaining for Molecular Subclassification of Head and Neck Squamous Cell Carcinomas

PurposeOur aim was to assess the ability of simultaneous immunohistochemical staining (IHC) for p16 and p53 to accurately subclassify head and neck squamous cell carcinomas (HNSCC) as HPV-associated (HPV-A) versus HPV-independent (HPV-I) and compare p53 IHC staining patterns to TP53 mutation status, p16 IHC positivity and HPV status.MethodsWe stained 31 HNSCCs for p53 and p16, and performed next-generation sequencing (FoundationOne©CDx) on all cases and HPV in-situ hybridization (ISH) when sufficient tissue was available (n = 23). p53 IHC staining patterns were assessed as wildtype (wt) or abnormal (abn) patterns i.e. overexpression, null or cytoplasmic staining.ResultsIn a majority of cases (28/31) interpretation of p16 and p53 IHC was straightforward; 10 were considered HPV-A (p16+/p53wt) and 18 cases were HPV-I (p16-/p53abn). In the remaining three tumours the unusual immunophenotype was resolved by molecular testing, specifically (i) subclonal p16 staining and wild type p53 staining in a tumour positive for HPV and with no TP53 mutation (HPV-A), (ii) negative p16 and wild type p53 staining with a TP53 mutation and negative for HPV (HPV-I), and (iii) equivocally increased p16 staining with mutant pattern p53 expression, negative HPV ISH and with a TP53 mutation (HPV-I).ConclusionPerforming p16 and p53 IHC staining simultaneously allows classification of most HNSCC as HPV-A (p16 +, p53 wild type (especially basal sparing or null-like HPV associated staining patterns, which were completely specific for HPV-A SCC) or HPV-I (p16 -, p53 mutant pattern expression), with the potential for limiting additional molecular HPV or mutational testing to selected cases only.

A study of the gaps and opportunities with fusion detection beyond NTRKs on 422 patients from the community.

e15186 Background: Gene fusions have important implications for therapeutic selection and patient quality of care and many fusions are targeted effectively in a tumor type agnostic manner. While most assays detect hundreds of fusions at once, typically the results are masked and analyzed according to medical requisition. Unfortunately, patients in the community setting most often are only tested for NTRK fusions, which have a prevalence of ~ 1%, and often following a positive IHC screen result. Here we compared side by side the clinical actionability gap in the community when using panTRK IHC testing and NGS fusion panels for NTRKs or for additional fusions, with both NGS panels selected presenting identical assay performance characteristics and medicare coverage. Methods: Clinical samples (n = 8307) from 33 tumor types were tested for RNA fusions using a hybridization capture RNA-seq based fusionome assay for solid tumors in our clinical laboratory, targeting RNA breakpoints at 1104 genes. Deidentified results were analyzed for either the 19 actionable fusion genes (ALK, BRAF, FGFR1-4, MET, NOTCH1/2, NRG1, NTRK1-3, PDGFB, PDGFRA/B, RAF1, RET and ROS1) reportable under Solid Tumor NGS fusion Panel, or only for NTRK fusions. Pan-TRK IHC results on fusion positive patients were analyzed. All the Deidentified patient data presented, was analyzed according to an IRB-approved protocol. Results: Targeted therapy -associated fusions were present in 422 (5.1%) patients, where 53% of patients were female with a median age of 68 years old, and 47% were male with a median age of 70 years old. However, when filtering only for NTRK fusions, just 104 (1.25%) patients had an actionable fusion (38 NTRK1, 10 NTRK2, 56 NTRK3). The additional 318 (3.8%) patients had other therapy candidate fusions: ALK (0.6%), BRAF 0.3%, FGFRs 0.9%, MET 0.4%, NOTCH2 0.2%, NRG1 0.2%, PDGFRA 0.1%, RAF1 0.2%, RET 0.5%, ROS1 0.2%, excluding NTRK positive cases. There were only 2 (0.02%) cases that were positive for both an NTRK fusion and an additional Targeted Panel fusion gene. Interestingly, we found that IHC testing was able to identify 75% of NTRK1 and 55% NTRK2 positive samples but only 20% of NTRK3 fusion positive patients. Moreover only 54% of the panTRK IHC positive patients expressed and NTRK fusion while 46% expressed one of the other 16 druggable fusions, with FGFRs on 20%, and ALK and ROS1 with 4% each. Conclusions: The data demonstrates that up to 4 -fold more patients can have a fusion matched therapy when testing for these 19 druggable fusions at once as compared to testing only for NTRK fusions or following IHC testing. Moreover, IHC testing as a screening method as very poor sensitivity for NTRK fusions, specially for NTRK3. Changes on the molecular testing paradigm in the community setting is needed to provide more patients with a therapeutic opportunity, when assay performance and financial considerations are equal to increase cancer care access.

Experience of personalizing cancer treatment in economically-constrained and resource-restricted community oncology practice in India through cost-effective broad spectrum NGS and survival outcomes: An observational study of 3 years.

e15173 Background: NGS based mutational findings are increasingly used in oncology practice to personalize treatment strategies. We elucidate the impact of comprehensive genomic profiling and the new avenues it opens for personalized precision medicine. Methods: This was a retrospective study evaluating patients who underwent a cost-effective (<US $1000), inhouse developed comprehensive NGS test. Descriptive data was tabulated & mutational distribution, therapeutic strategies and survival outcomes were evaluated. Results: A total of 336 patients were evaluated from a community oncology practice over the last 3 years in Western India. The mean age was 59.2 years; with F:M being 1.04:1 and stage distribution being 3.5%, 5.9%, 9.5% and 80.9% for Stage I, II, III and IV respectively. Comprehensive NGS was performed to evaluate SNVs, CNVs, and indels spanning across over 15000 loci for 1080 tumor specific genes wherein 71.7% were tissue-based, 24.4% were liquid biopsy-based and 3.8% were combined tissue-DNA and ctDNA-based analysis. Majority (69.9%) of the patients were pre-treated while 30% were therapy naïve. The most common cancers evaluated were Lung (18.1%), Pancreatobiliary (15.1%), Breast (11.3%), Gynaec (9.5%), and Lower GI (9.5%). Pathogenic mutations were reported in 83.6% of the cohort while in 16.3% no mutations were detected. Most common mutations observed in this retrospective study were TP53 (38.3%), KRAS (16.6%), PIK3CA (9.5%), EGFR (7.4%) and PTEN (5.6%); and the distribution was largely similar in untreated as well as pre-treated cohorts. Furthermore, genomic alterations for each cancer type are described in Table 1. MSI high and TMB high (>10) were reported in 0.5% and 7.4% respectively. PDL1 positive IHC was reported in 3.2% of tissue samples, whereas HRD high (>50) was reported in 2.3% of the cohort of which the majority (11.5%) were from Upper GI tumors. Targetable genomic alterations were detected in 53.8% (181/336) of which 38.1%(69/181) received the suggested targeted therapy. Clinical response was seen as PR in 14.4% and CR in 2.8% of patients. Of 336 patients 4.76% received modified therapeutic regimens which differed from the standard of care, wherein median PFS was 8 mo [CI 95% (5.3-10.7)] while median OS was 55.1 mo [CI 95% (25.8-NA)]. Conclusions: This observational study outlines the potential benefit of personalizing treatment regimens in the management of solid organ cancers, especially in scenarios where standard-of-care regimens may have failed and the need to incorporate broad-spectrum NGS. [Table: see text]

Molecular and immunological characterization of androgen receptor expression in different breast cancer subtypes.

1114 Background: While estrogen receptor (ER) is well-studied in breast cancer (BC), the role of androgen receptor (AR) in prognosis and therapy response is less understood. Here, we aimed to characterize the clinicopathologic and molecular features of AR gene expression in BC subtypes. Methods: 10,728 BC samples were tested by NGS (592, NextSeq; WES, NovaSeq) and WTS (NovaSeq; Caris Life Sciences, Phoenix, AZ). MSI was tested by IHC and NGS. TMB-high was designated as >10 somatic mutations/MB. Tumors with AR-high(H) and AR-low(L) RNA expression were classified by top and bottom quartile, respectively. Real world overall survival (OS) and treatment-associated survival was obtained from insurance claims and calculated from treatment start to last contact using Kaplan-Meier estimates. Statistical significance was determined by chi-square and Mann-Whitney U test with p-values adjusted for multiple comparisons ( q<.05). Results: Lobular carcinoma had higher AR expression (2.37-fold) and AR positivity by IHC (93.6% vs 63.6%) compared to ductal carcinoma ( q<.05). Luminal A (LumA) had higher AR expression and IHC positivity compared to HER2-enriched, basal-like, and normal-like tumors ( q<.05). AR-H tumors were significantly ( p<.05) enriched for PIK3CA mutations in LumA (60.3% vs 29.8%), LumB (48.1% vs 23.2%), HER2-enriched (51.2% vs 39.3%), and basal-like (23.8% vs 8.3%); CDH1 mutations in LumA (26% vs 10.3%) and normal-like (55.5% vs 4.8%); MAP3K1 in LumA (17.1% vs 5.3%); ESR1 in LumB (17.9% vs 10.7%); and NF1 in HER2-enriched (19.3% vs 7.1%). AR-H had higher immune infiltration for LumA (B cells, M2 Mφ, neutrophils, NK cells, DC), LumB (B cells, M2 Mφ, neutrophils, NK cells, CD4+ T cells, DC), basal-like (NK cells, CD4+ T cells), and normal-like (NK cells, DC; q<.05) than AR-L. Conversely, AR-H HER2-enriched tumors had lower immune infiltration (B cells, M1 and M2 Mφ, NK cells, CD8+ T cells, DC) and fewer TMB-high (15.1% vs 23.2%), dMMR/MSI-high (0.3% vs 2%), and PD-L1+ tumors (15% vs 40.8%; p<.05) compared to AR-L (all q<.05). Post-doxorubicin survival was longer for patients with AR-H tumors; however, opposing trends were observed for patients with LumB (75.5 vs 56.3 m; p=.081) and HER2-enriched tumors (47.9 vs 65.2 m; p.071). AR-H was associated with longer post-dox survival in patients with LumB PIK3CA-mt tumors (81.7 vs 39.3 m; p=.036), but shorter post-dox survival in HER2-enriched PIK3CA-wt (50.4 vs 70.4 m) and PIK3CA-mt cohorts (40.8 vs 58.0 m; p=.18). Conclusions: Findings from our updated analysis based on PAM50 designation suggest a strong association between AR and PIK3CA mutations across subtypes and suggest that distinct AR-associated alterations in the immune microenvironment require further study. Exploration of specific mutations and immune-oncology markers associated with AR-H may aid in molecularly selected clinical trial design for advanced BC patients.

Immune checkpoint inhibitor treatment in PD-L1-negative gastroesophageal cancer tumors.

e16062 Background: We aimed to investigate whether there is a subgroup of patients with gastroesophageal cancers who, despite having IHC-PD-L1 negative tumors, might still benefit from ICI treatment. Furthermore, the impact of ICI treatment on patients with tumors that are PD-L1 negative by IHC but exhibit high CD274 (PD-L1) expression remains undefined. Methods: 1,416 esophageal adenocarcinomas (EA), 486 esophageal squamous carcinomas (ES), 859 esophagogastric junction adenocarcinomas (EJA), and 1,613 gastric adenocarcinoma (GA) samples were analyzed using NGS of DNA (NextSeq, 592 genes and NovaSeq, WES) and RNA (NovaSeq, WTS) (Caris Life Sciences, Phx, AZ). PD-L1 IHC positivity was defined as > 1% CPS (Agilent's 22c3). Correlation between PD-L1 CPS and CD274 expression (transcripts per million – TPM) were assessed by Spearman’s coefficient. Tumors were divided into CD274-H (high expression) and CD274-L (low expression) cohorts, representing the top 25% and bottom 25% of expression levels, respectively. Real-world overall survival (OS) data were obtained from insurance claims records and analyzed using Cox proportional hazards with hazard ratios (HR) and log-rank tests. Results: Weak correlations were observed between PD-L1 CPS and CD274 expression in adenocarcinoma histology tumors (EA: 0.374, EJA: 0.358, GA: 0.387), while a stronger correlation was found in squamous tumors (ES: 0.537). Median CD274 expression was significantly higher in PD-L1+ compared to PD-L1- ES tumors (2.65-fold) and in EA (1.68-fold), EJA (1.92-fold), and GA (1.96-fold) tumors (p < 0.001). In PD-L1 IHC-negative ES, there was no association between CD274-H expression and OS (H 12.4 vs L 10.6 mo; HR 0.90, p = 0.48). However, in adenocarcinomas, CD274-H showed a slightly improved OS (12.8 vs 11.3 mo; HR 0.79, p < 0.05). CD274-H trended towards worse post-Carboplatin/paclitaxel (CP) OS (ES: 13.8 vs 18.2 mo; HR 1.60; p = 0.22; Adenocarcinoma: 18.2 vs 27.4 mo; HR 1.50, p = 0.19). Interestingly, CD274-H was associated with improved post-CP/nivolumab survival in ES (96.5 vs 28 mo; HR 0.32; p = 0.047), with a similar but not statistically significant pattern in Adenocarcinoma EGC (Not Reached vs 30.2 mo; HR 0.39, p = 0.23). Furthermore, in CD274-L GEC, there was no difference in post-treatment survival with the addition of Nivolumab to CP (Squamous: 30 vs 18.2 mo; HR 0.91, p = 0.83; Adenocarcinoma: 30.2 vs 27.4 mo; HR 1.14; p = 0.76). In contrast, CD274-H showed improved survival with the addition of Nivolumab (Squamous: 96.5 mo vs 13.8 mo; HR 0.15; p = 0.01; Adenocarcinoma: NR vs 18.2 mo; HR 0.30; p = 0.08). Conclusions: High CD274 expression was associated with improved survival when Nivolumab was added to chemotherapy in patients with PD-L1-negative tumors. Further investigation is needed to confirm the potential benefits of Nivolumab treatment in gastroesophageal cancer patients with tumors that are PD-L1-negative by IHC but exhibit high mRNA expression.

Abstract PS10-04: The Landscape of Somatic Genetic Alterations in Breast Cancers from Carriers of Germline Pathogenic Variants in DNA-repair Genes

Abstract Background: Hereditary breast cancer in carriers of germline pathogenic or likely pathogenic variants (PVs) in ATM, BRCA1, BRCA2, CHEK2, and PALB2 have unique clinicopathological characteristics compared to sporadic breast cancer. However, very little is known about the underlying differences in somatic genetic alterations between hereditary and sporadic breast cancer. Methods: The study included 7,533 individuals with breast cancer subjected to Tempus xT tumor-normal matched sequencing (596-648 genes). The frequencies of the somatic genetic alterations in each gene were compared separately between tumors arising in individuals with incidental germline PVs (gATM, gBRCA1, gBRCA2, gCHEK2, gPALB2) and sporadic breast tumors. Sporadic tumors were identified as individuals with no detected incidental germline PVs in these 5 genes. Comparisons were made by either Pearson’s Chi-squared or Fisher’s exact test, with false discovery rate (FDR) correction for multiple testing. Breast cancer subtype was determined based on the record of IHC positivity for ER, PR, or HER2. Detection of ERBB2 (HER2) gene amplifications via DNA sequencing was also used to classify samples as HER2+ in the absence of available IHC data. Results: The median age at breast cancer diagnosis for the cohort was 56 years. More than two-thirds of the patients were White (73%) while 14% identified as Black or African American. The overall frequency of incidental germline PVs in each gene was 0.8% for gATM, 1.4% for gBRCA1, 2.1% for gBRCA2, 1.0% for CHEK2, and 0.7% for PALB2. A total of 3,648 (48.4%) tumors were ER+/PR+/HER2-, 1,297 (17.2%) were triple-negative (TNBC), 841 (11.2%) were HER2+ and 1,747 (23.2%) could not be classified due to missing ER, PR or HER2 status, or absence of detected ERBB2 amplifications. Among ER+/PR+/HER2- breast cancers, compared to sporadic tumors, ESR1 mutations were significantly enriched in gATM carriers (33% vs. 11%, q-value 0.05), TP53 alterations were significantly enriched in gBRCA1 PV carriers (69% vs. 30%, q-value < 0.001) but depleted in gATM (12% vs. 30%, q-value 0.4) and gCHEK2 PV carriers (5.4% vs. 30%, q-value 0.06), and PIK3CA (14% vs. 35%, q-value 0.001) and CCND1 (3.4% vs. 17%, q-value 0.02) alterations were significantly lower in gBRCA2 PV carriers. Among TNBC, TP53 alterations were also significantly higher in gBRCA1 PV carriers compared to sporadic tumors (96% vs. 69%, q-value 0.004). In HER2+ breast cancers, ERBB2 alterations were observed in approximately two-thirds of the tumors, and a significant difference was not observed between incidental hereditary and sporadic tumors. Among ER+/PR+/HER2- tumors, although not statistically significant, the frequency of ESR1 (3.1% vs. 11%, q-value >0.9), PIK3CA (12% vs. 35%, q-value 0.2) alterations were lower in incidental gBRCA1 versus sporadic tumors, FGFR1 alterations were lower in incidental gBRCA1 (6.2% vs. 13%, q-value >0.9) and incidental gBRCA2 (3.4% vs. 13%, q-value 0.13) but enriched in incidental gATM (33% vs. 13%, q-value 0.05). Conclusions: The observed differences in the frequencies of CCND1, ESR1, PIK3CA, TP53, and other key genetic alterations between incidental hereditary and sporadic breast cancer highlight the unique tumor biology of breast cancer in germline PV carriers and have significant implications for understanding tumorigenesis and identifying therapeutic strategies for the management of hereditary breast cancer. Citation Format: Minxuan Huang, Melissa Stoppler. The Landscape of Somatic Genetic Alterations in Breast Cancers from Carriers of Germline Pathogenic Variants in DNA-repair Genes [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS10-04.

Abstract 1030: Concordance between the DESTINY-Breast04 clinical trial assay (4B5[CDx]) and other HER2 IHC assays for HER2-low breast cancer in real-world practice: First phase of a large-scale, multicenter global ring study

Abstract Background: DESTINY-Breast04 (DB-04) showed that trastuzumab deruxtecan improves survival vs chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-low (immunohistochemistry [IHC] 1+ or IHC 2+ with in situ hybridization negative) metastatic breast cancer (BC). The VENTANA 4B5(CDx) IHC assay, now approved in the United States (US) as a companion diagnostic, was used as the clinical trial assay (CTA) in DB-04. Real-world differentiation of HER2-low vs HER2 IHC 0 BC with non-CTAs is difficult. This is the first phase of a study assessing agreement between CTA and non-CTA scores. Methods: 50 clinical BC samples with HER2 IHC scores of 0, 1+, 2+, and 3+ were sent to laboratories in Europe, Canada, and the US for HER2 IHC testing per ASCO/CAP 2018 guidelines. After routine protocol scoring, pathologists were trained and rescored the samples 2 weeks later. Post training scores were compared with reference CTA scores determined by a central laboratory and a panel of experts. The primary endpoint was positive percentage agreement (PPA) and negative percentage agreement (NPA) between CTA and non-CTA scores, assessed after training, considering HER2-low as positive and HER2 IHC 0 as negative. Results: A total of 3449 post training non-CTA scores were available for analysis. PPA for HER2-low vs HER2 IHC 0 was 87.5% and NPA was 61.9%, with Cohen κ of 0.51 (Table). HER2-low vs HER2 IHC 0 agreement between CTA and non-CTA varied across subgroups. PPA >95% was shown with 4B5 Laboratory Developed Tests (LDTs) and HercepTest (Omnis), NPA of 80% with Leica, and overall agreement >80% with HercepTest (Link48), 4B5 LDTs, and German, French, and Italian laboratories. Conclusions: The degree of concordance between the CTA and non-CTAs varied among assay types and laboratory locations. A low NPA for some non-CTAs suggests the need for further assay optimization for HER2 IHC 0 evaluation. Post training non-CTA results HER2-low vs HER2 IHC 0 BC Post training scores PPA (95% CI), % NPA (95% CI), % Overall percentage agreement (95% CI), % Cohen κ (95% CI) Overall non-CTA test results (N = 3449) 87.5 (86.0-89.0) 61.9 (58.9-64.9) 78.7 (77.1-80.1) 0.51 (0.48-0.54) Non-CTA subgroups HercepTest (Omnis) (n = 467) 95.5 (92.3-97.7) 36.9 (28.9-45.4) 75.2 (70.8-79.4) 0.37 (0.28-0.46) HercepTest (Link48) (n = 790) 88.5 (85.2-91.2) 64.3 (57.8-70.4) 80.3 (77.2-83.2) 0.55 (0.48-0.61) Leica (n = 96) 59.3 (45.0-72.4) 80.0 (61.4-92.3) 66.7 (55.5-76.6) 0.35 (0.17-0.53) Non-4B5 LDTs (n = 1609) 83.8 (81.2-86.1) 67.8 (63.5-72.0) 78.2 (75.9-80.3) 0.52 (0.47-0.57) 4B5 LDTs (n = 487) 96.0 (93.0-98.0) 58.8 (50.4-66.8) 83.0 (79.1-86.4) 0.59 (0.51-0.68) Country subgroups Germany (n = 340) 93.1 (88.5-96.3) 64.4 (54.2-73.6) 83.1 (78.3-87.2) 0.61 (0.51-0.70) France (n = 342) 95.4 (91.5-97.9) 64.4 (54.4-73.6) 84.7 (80.1-88.6) 0.64 (0.55-0.73) Italy (n = 395) 89.9 (85.2-93.5) 72.5 (63.6-80.3) 83.9 (79.6-87.6) 0.64 (0.55-0.72) Spain (n = 567) 83.0 (78.4-86.9) 64.2 (56.6-71.3) 76.3 (72.3-80.0) 0.48 (0.40-0.56) US/Canada (n = 1029) 86.6 (83.6-89.2) 61.8 (56.1-67.3) 78.2 (75.4-80.8) 0.50 (0.44-0.56) Europe, other (n = 776) 85.0 (81.3-88.2) 52.8 (46.2-59.3) 73.8 (70.3-77.1) 0.40 (0.32-0.47) Citation Format: Hans-Ulrich Schildhaus, Sunil Badve, Corrado D’Arrigo, Gelareh Farshid, Annette Lebeau, Vicente Peg, Fréderique Penault-Llorca, Josef Rueschoff, Wentao Yang, Neil Atkey, Jessica Baumann, Elisabeth Beyerlein, Amy Hanlon Newell, Alexander Penner, Akira Moh, Guiseppe Viale. Concordance between the DESTINY-Breast04 clinical trial assay (4B5[CDx]) and other HER2 IHC assays for HER2-low breast cancer in real-world practice: First phase of a large-scale, multicenter global ring study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1030.

Abstract 7526: Landscape of TIGIT and PD-L1 co-expression in solid tumors

Abstract Background: Combination treatment of solid tumors with anti-PD-1/PD-L1 and anti-TIGIT agents have shown promise in recent clinical trials. However, TIGIT co-expression with other checkpoints has not been comprehensively characterized to support identification and prioritization of patients most likely to benefit from anti-TIGIT drugs and guide clinical trial design. In this study, we investigate TIGIT and other PD-1/PD-L1 axis checkpoint targets across various solid tumors. Methods: A discovery cohort (DC) of 24,186 solid tumors across 35 tumor types was evaluated by comprehensive immune profiling. TIGIT gene expression was normalized and ranked yielding a percentile rank values [0-100]. TIGIT rank was classified as high (rank >e 75) and low (rank < 25). We studied the distribution of TIGIT expression, cellular proliferation signature, and co-expression with PD-1/PD-L1 axis and other checkpoint targets using Spearman correlation(rs). Kaplan-Meier analysis and Chi-squared assessed associations between TIGIT expression/checkpoint co-expression and overall survival (OS), progression free survival (PFS) and objective response rate (ORR) differences in a separate cohort of 72 pembrolizumab treated non-small cell lung cancer (LC) patients treated with pembrolizumab. Results: The DC confirmed a large range of TIGIT expression with highest median expression observed in NSCLC (median = 61), head & neck (HNSCC) (median = 59), and cervical cancer (median = 55). Significant association between PD-L1 IHC positivity (TPS≥1%, CPS≥1) and TIGIT expression (p<0.001) was discovered, where 69% (n=3574) of TIGIT high cases were PD-L1 positive, whereas 66% (n=3606) of TIGIT low cases were PD-L1 negative. By RNA-seq measurements, significant TIGIT co-expression (p<0.001) with various checkpoint blockade targets including PD-1 (rs=0.5), PD-L1 (rs=0.5), and TIM3 (rs=0.6) was confirmed. In the LC, patients with TIGIT high tumors had significantly improved OS (median OS = 44 months; p=0.01) and PFS (median PFS = 35 months; p=0.006) compared TIGIT low group (median OS = 23 months; median PFS = 18 months). Similar results were observed for response to pembrolizumab, where TIGIT high cases had significantly higher response (ORR=60%, p= 0.001) vs. TIGIT low cases (ORR=39%). This was confirmed in TIGIT high and PD-L1-IHC positive group with improved OS (p=0.013), PFS (p=0.017) and ORR (p=0.016). Conclusion: In an ultra-large cohort of clinically tested solid tumors, TIGIT was differentially expressed across tumor histologies of solid tumors. TIGIT expression was strongly co-expressed with PD-1/PD-L1 axis, supporting the improved outcomes for patients with NSCLC treated with a combination of TIGIT and PD-1/PD-L1 inhibitors from recent clinical trials. This finding of co-expression pattern of TIGIT and PD-1/PD-L1 axis highlights the potential use of immune profiling for combination therapy strategies and clinical trial design in solid tumors. Citation Format: Sarabjot Pabla, Maria-Fernanda Senosain, R.J. Seager, Hardik Parikh, Erik Van Roey, Shuang Gao, Yamuna Pulivendula, Paul DePietro, Mary Nesline, Durgapras Dash, Jeffrey M. Conroy, Stephanie Hastings, Heidi Ko, Kyle C. Strickland, Rebecca A. Previs, Eric Severson, Marcia Eisenberg, Brian Caveney, Taylor J. Jensen, Shakti Ramkissoon. Landscape of TIGIT and PD-L1 co-expression in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7526.

Fine-needle aspiration diagnosis of secondary malignant tumors of the thyroid gland: A single-institution experience of 17 cases.

Fine-needle aspiration (FNA) is the most commonly used preoperative pathological diagnostic tool for thyroid tumors. Secondary malignant tumors of the thyroid gland account for less than 3% of all thyroid malignancies. The aim of this study was to investigate the types and cytopathological features of secondary thyroid tumors, evaluate diagnostic pitfalls in FNA. Cases of secondary thyroid tumors diagnosed in the Department of Pathology of Shaanxi Provincial People's Hospital were collected, and their clinical data, cytologic features, immunohistochemical results, and histopathological diagnoses were summarized. The study included 17 cases (8 males and 9 females) with a mean age of 60.4 ± 9.4 years (range, 45-83 years). Six cases had a known history of primary malignancy prior to FNA aspiration diagnosis. The most common organs of origin were the lungs (5 cases, 3 adenocarcinoma, and 2 small-cell carcinoma) and esophagus (5 cases, 3 squamous-cell carcinoma, 1 adenocarcinoma, and 1 small-cell carcinoma). The next most common was squamous-cell carcinoma of the larynx (3 cases), and gastric tumor (2 cases), including 1 lymphoma and 1 adenocarcinoma. Cell blocks and immunohistochemistry were performed in 12 of these cases. Comparison of the impact of positive history and IHC availability on the accuracy of pathologic diagnosis showed that both were statistically significant. FNA is an effective means of diagnosing secondary malignancies of the thyroid, in which knowledge of the patient's history of malignancy is essential, and the use of cell blocks and immunohistochemistry helps to clarify the pathological diagnosis.

Cervical Intraepithelial Neoplasia grade 2 biopsy: Do p16INK4a and Ki-67 biomarkers contribute to the decision to treat? A cross-sectional study.

Managing cervical intraepithelial neoplasia grade 2 (CIN2) is challenging, considering the CIN2 regression rate, perinatal risks associated with excisional procedures, and insufficient well-established risk factors to predict progression. To determine the ability of p16INK4a and Ki-67 staining in biopsies diagnosed with CIN2 to identify patients with higher-grade lesions (CIN3 or carcinoma). Cross-sectional study conducted at a referral center for treating uterine cervical lesions. In 79 women, we analyzed the correlation of p16INK4a and Ki-67 expression in CIN2 biopsies with the presence of a higher-grade lesions, as determined via histopathology in surgical specimens from treated women or via two colposcopies and two cytological tests during follow-up for untreated women with at least a 6-month interval. The expression of these two biomarkers was verified by at least two independent pathologists and quantified using digital algorithms. Thirteen (16.8%) women with CIN2 biopsy exhibited higher-grade lesions on the surgical excision specimen or during follow-up. p16INK4a expression positively and negatively predicted the presence of higher-grade lesions in 17.19% and 86.67% patients, respectively. Ki-67 expression positively and negatively predicted the presence of higher-grade lesions in 40% and 88.24% patients, respectively. Negative p16INK4a and Ki67 immunohistochemical staining can assure absence of a higher-grade lesion in more than 85% of patients with CIN2 biopsies and can be used to prevent overtreatment of these patients. Positive IHC staining for p16INK4a and Ki-67 did not predict CIN3 in patients with CIN2 biopsies.

Death Due to Anaphylactic Reaction: The Role of the Forensic Pathologist in an Accurate Postmortem Diagnosis.

Background and Objectives: The diagnosis of anaphylaxis comprehensively depends on both situational information and laboratory investigations. For this purpose, serum tryptase concentration is examined as an indicator of systemic mast cell mediator release, linked to an underlying anaphylactic process. Increased levels of tryptase may occur in some events different from anaphylaxis, but usually information from crime scene investigations is lacking and autoptic findings are not specific. For legal reasons, it is required to achieve a definite diagnosis of mast cell degranulation that can lead to a certain diagnosis of death from anaphylaxis. Immunohistochemistry seems to be a relatively simple, reliable, and easily repeatable method that can assist the forensic pathologist in the differential diagnosis of death from anaphylaxis. Materials and Methods: This work provides an overview of the current literature on immunohistochemical methods useful in the determination process of anaphylactic-related deaths. A systematic search, according to the PRISMA statement, was performed in databases to identify studies investigating immunohistochemical targets related to anaphylaxis death. Results: This work underscores the importance of anaphylaxis mediators such as tryptase, CD117, and chymase in the immunohistochemical analysis of anaphylactic deaths. Conclusions: According to the reviewed literature, the diagnosis of death due to anaphylaxis should depend not just on the suspicion of an anaphylactic reaction but also on confirming mast cell degranulation through the identification of IHC positivity for inflammatory mediators, particularly in the respiratory tract.

Comparison of SP142 and 22C3 PD-L1 assays in a population-based cohort of triple-negative breast cancer patients in the context of their clinically established scoring algorithms

BackgroundImmunohistochemical (IHC) PD-L1 expression is commonly employed as predictive biomarker for checkpoint inhibitors in triple-negative breast cancer (TNBC). However, IHC evaluation methods are non-uniform and further studies are needed to optimize clinical utility.MethodsWe compared the concordance, prognostic value and gene expression between PD-L1 IHC expression by SP142 immune cell (IC) score and 22C3 combined positive score (CPS; companion IHC diagnostic assays for atezolizumab and pembrolizumab, respectively) in a population-based cohort of 232 early-stage TNBC patients.ResultsThe expression rates of PD-L1 for SP142 IC ≥ 1%, 22C3 CPS ≥ 10, 22C3 CPS ≥ 1 and 22C3 IC ≥ 1% were 50.9%, 27.2%, 53.9% and 41.8%, respectively. The analytical concordance (kappa values) between SP142 IC+ and these three different 22C3 scorings were 73.7% (0.48, weak agreement), 81.5% (0.63) and 86.6% (0.73), respectively. The SP142 assay was better at identifying 22C3 positive tumors than the 22C3 assay was at detecting SP142 positive tumors. PD-L1 (CD274) gene expression (mRNA) showed a strong positive association with all two-categorical IHC scorings of the PD-L1 expression, irrespective of antibody and cut-off (Spearman Rho ranged from 0.59 to 0.62; all p-values < 0.001). PD-L1 IHC positivity and abundance of tumor infiltrating lymphocytes were of positive prognostic value in univariable regression analyses in patients treated with (neo)adjuvant chemotherapy, where it was strongest for 22C3 CPS ≥ 10 and distant relapse-free interval (HR = 0.18, p = 0.019). However, PD-L1 status was not independently prognostic when adjusting for abundance of tumor infiltrating lymphocytes in multivariable analyses.ConclusionOur findings support that the SP142 and 22C3 IHC assays, with their respective clinically applied scoring algorithms, are not analytically equivalent where they identify partially non-overlapping subpopulations of TNBC patients and cannot be substituted with one another regarding PD-L1 detection.Trial registration The Swedish Cancerome Analysis Network - Breast (SCAN-B) study, retrospectively registered 2nd Dec 2014 at ClinicalTrials.gov; ID NCT02306096.

Large Solitary Fibrous Tumor (SFT) of the penis- a case report and review of literature

BackgroundSolitary fibrous tumors (SFTs) are very rare spindle cell neoplasms of mesenchymal origin with largely benign course of disease. Genital SFT’s can be managed providing excellent functional and psychological outcomes by timely intervention.Case presentationWe report the largest and possibly the second only reported case of penile SFT in a 34 year male presenting with a gradually increasing perineal mass with clinically normal appearing phallus. MRI revealed a 9.8 × 3.2 cm soft tissue mass arising from left corpora cavernosae, the mass was excised en-bloc via a perineal approach under spinal anaesthesia. Histopathology revealed spindle cell tumor embedded in myxohyaline stroma along with hyalinized vascular channels demonstrating IHC positivity for CD34 and STAT6. The patient is disease free post 2 years of resection with no sexual or urinary dysfunctions.ConclusionGenital SFTs, although rare, should be considered in the differential diagnosis of well-circumscribed, painless, slow growing solid masses and histopathologists must be vigilant of its malignant characteristics.

Soft Tissue Sarcoma Mimicking Melanoma: A Systematic Review.

Sarcoma may show similarities to malignant melanoma in terms of morphologic and immunohistochemical aspects, making it difficult to differentiate between these two neoplasms during the diagnostic process. This systematic review aims to summarize available evidence on cases of sarcoma that were initially diagnosed as melanoma. A comprehensive search of the MEDLINE/Pubmed, EMBASE, and SCOPUS databases was conducted through March 2023. We included case series and case reports of sarcoma patients that were initially diagnosed as malignant melanoma. PRISMA guidelines were followed. Twenty-three case reports and four case series with a total of 34 patients were included. The clinical presentation was heterogeneous, and the most involved anatomical regions were lower limbs (24%), head/neck (24%), and upper limbs (21%). IHC positivity was reported for S100 (69%), HMB45 (63%), MelanA (31%), and MiTF (3%). The main reasons for a second assessment were unusual presentation (48%) and uncertain diagnosis (28%). EWSR1 translocation was investigated in 17/34 patients (50%) and found to be positive in 16/17 (94%). The final diagnosis was clear cell sarcoma (50%) or other soft tissue sarcomas (50%). Melanoma and some histotypes of sarcoma share many similarities. In cases of atypical lesions, a second diagnosis should be considered, and ESWR1 translocation should be investigated.

Phase 1 multicenter dose escalation and dose expansion study of antibody-drug conjugate (ADC) MYTX-011 in subjects with non-small cell lung cancer.

TPS9147 Background: cMET is a receptor tyrosine kinase and proto-oncogene whose activity is upregulated across a wide range of cancers. In NSCLC, expression of cMET is upregulated by DNA amplification (2% to 5%), exon 14 skipping mutations (2% to 4%), and overexpression (30% to 60%). In NSCLC, cMET upregulation has also been demonstrated to be a resistance mechanism for several approved EGFR-targeted kinase inhibitors, and this may limit their effectiveness. Despite the approval of MET tyrosine kinase inhibitors, almost half of patients do not respond to these inhibitors and resistance is inevitable. MYTX-011 is an ADC incorporating the clinically validated vcMMAE linker-payload conjugated to a novel, pH-dependent anti-cMET antibody. In preclinical studies, MYTX-011, compared to a surrogate of an advanced clinical stage cMET ADC, showed markedly higher ( &gt; 3 fold) internalization and increased cytotoxicity in cMET+ tumor cells in vitro, which translates to greater (≥3 fold) efficacy in high or moderate c-Met+ xenograft models in vivo. PK and toxicity studies revealed that MYTX-011 exhibited favorable PK characteristics, and a toxicity profile similar to previously described MMAE-based ADCs. Methods: MYTX-011-01 (ClinicalTrials.gov Identifier: NCT05652868) is a first-in-human Phase 1 dose escalation and dose expansion study. MYTX-011 will be administered intravenously every 21 days for a maximum of 2 years. Part 1 (dose escalation) will assess the safety and tolerability of MYTX-011 in patients with advanced NSCLC and identify the recommended Phase 2 dose (RP2D). Part 2 (dose expansion) will include subjects with NSCLC with cMET overexpression or MET amplification/exon 14 skipping mutations. In Part 1, subjects will be enrolled to evaluate the safety of escalating doses of MYTX-011 as a single-agent and to establish the RP2D and/or MTD. The dose escalation scheme is based on a 3-subject cohort minimum Bayesian Optimal Interval (BOIN) design. The RP2D will be selected as a biologically active dose at or below the MTD (or the highest dose tested if an MTD is not identified during the study) and will be informed by safety, tolerability, pharmacokinetic data, and preliminary anti-tumor activity of MYTX-011 based on RECIST 1.1. Part 2 of the study will be initiated once the RP2D has been determined and will enroll subjects into different cohorts based on cMET IHC positivity cutoff and/or presence of MET genetic alterations ( MET amplification or exon 14 skipping). All cohorts are defined to explore preliminary antitumor activity in populations with different thresholds of cMET positivity that were selected based on data for cMET expression and efficacy observed with MYTX-011 in preclinical models, published data for responses to cMET targeting agents, and on the prevalence of subject tumors with different expression levels. Enrollment in the MYTX-011-01 study is ongoing. Clinical trial information: NCT05652868 .

P16 expression as a diagnostic parameter of endometrial carcinoma and endometrial hyperplasia

Background: Endometrial cancer is malignant epithelial neoplasm originating from endometrium; endometrial cancer is the sixth most common cancer in women and the fifteenth most common cancer worldwide. The aim of study is to evaluate the expression of P16 IHC in endometrial carcinoma; and its diagnostic role in different histopathological types of endometrial carcinoma. Method: Retrospective study of 70 cases with collection of paraffin embedded tissue blocks and clinical data of patients with endometrial carcinoma and endometrial hyperplasia. H&E staining of slides done to confirm the histopathological diagnosis by specialist pathologist and then stained immunohistochemically for P16 marker. Results: In the current study, the average age of women was 32 to 78 years with a mean age of 53.42. More than half of the women with endometrial carcinoma (EC) (66.6%) presented in the age group between 50 and 70 years, half of the patients with atypical hyperplasia (50%) fall in the same age group as endometrial carcinoma, and the rest of the atypical hyperplasia patients and 65% of those without atypia presented in younger ages (30-50 years’ age group). (63.3%) of patients with endometrial cancer had postmenopausal bleeding; 70% of patients with atypical endometrial hyperplasia and 75% of those without atypia had excessive monthly bleeding (HMB). Histopathology correlated with patient age and clinical presentation. P16 immune marker expression did not correlate with stage at diagnosis of endometrial cancer in TAH & BSO instances. All endometrial serous carcinoma and more than half of EEC had positive p16 IHC. Endometrial hyperplasia had no P16 IHC expression, although more than half of endometrial cancer cases did. Conclusion: All endometrial serous carcinomas expressed high P16 IHC stain. More than half of endometrioid carcinomas had p16 IHC stain, with significant expression in high-grade morphological sections (FIGO 3). Most low-grade endometrioid carcinomas are P16-negative. P16 loss in all endometrial hyperplasia. P16 immunohistochemistry marker aids endometrial carcinoma diagnosis.

Abstract PD9-09: Molecular differences between younger versus older estrogen receptor positive/human epidermal growth factor receptor-2 negative breast cancers

Abstract Background: The RxPONDER and TAILORx trials demonstrated benefit from adjuvant chemotherapy in patients &amp;lt; 50 years with node-positive breast cancer and Recurrence Score (RS) 0-25, and with node-negative disease and RS 16-25, respectively. Neither trial showed benefit in older women with RS &amp;lt; 26. It is unclear what explains the interaction between age and adjuvant chemotherapy benefit. Methods: We analyzed transcriptomic and genomic data from n=4,507 ER+/HER2- breast cancers to compare differences in estrogen receptor (ER), proliferation, and immune-related gene expressions, and somatic mutation patterns and mutation burden between younger (&amp;lt; 50 years of age) and older (&amp;gt;55 years) patients. We restricted our analysis to patients in the lower 80% range of in silico RS distribution to mimic the RxPONDER and TAILORx populations. Results: Five data sets were analyzed independently to assess consistency of results (TCGA n=530; microarray cohort A n=865; Cohort B n=609, METABRIC n=867, SCAN-B n=1636). Older patients had significantly higher somatic mutation burden and more frequent copy number gain in ESR1, LATS1, ARID1B, SGK1, and MYB genes (odds ratio [OR] &amp;gt; 8.5, FDR&amp;lt; 0.05), but lower frequency of GATA3 mutations (12% versus 26%, P&amp;lt; 0.0001). Younger patients had higher rate of ESR1 copy number loss (OR: 0.45, FDR: 0.03). There was no difference in proliferation-related gene expression. ESR1 mRNA expression was significantly lower in younger women in all cohorts (P &amp;lt; 0.001). A regression model of ESR1 mRNA expression using age and ER IHC positivity indicated that lower ER expression in younger patients is primarily driven by lower ESR1 mRNA per cancer cell and not by fewer ER positive cells. We also assessed four gene signatures associated with endocrine therapy sensitivity including a 4-gene ERS, a 7-gene ERS-Lum, a 106-gene ERS-Pos signature, and a 59-gene ERS-Neg signature associated with endocrine resistance. In the TCGA and METABRIC cohorts, the ERS, ERS-Lum, and ERS-Pos signatures were all lower (FDR&amp;lt; 0.03) while the ERS-Neg signature was higher (FDR&amp;lt; 0.001) in younger patients. Similarly, in both microarray cohorts, and in the SCAN-B-cohort, the ERS-Pos signature was lower and the ERS-Neg signature was higher in younger patients (FDR&amp;lt; 0.002). Next, we assessed 4 different immune cell signatures that have been associated with response to chemotherapy. In the TCGA, B-cell, T-cell, Mast-cell, and TIS signatures were significantly higher (FDR&amp;lt;.05). In the microarray Cohort-A, B cells and mast cells were significantly higher, and the T cell and TIS signatures showed a trend for higher expression. In Cohort-B, T cells, B cells, TIS, and dendritic cells signatures were significantly higher in younger patients. Significantly higher expression of immune gene signatures in younger patients were also seen in the METABRIC and SCAN-B data sets. The ER-related and immune-related gene signatures showed negative correlation and joint analysis defined three subpopulations in younger women: (i) immune-high/ER-low, (ii) immune-intermediate/ER-intermediate and (iii) immune-low/ER-intermediate, whereas in older women the dominant pattern was immune-low/ER-high. Conclusion: ESR1 mRNA and ER-associated gene expression is lower in ER positive cancers of younger compared to older patients, while immune infiltration is higher. The cytotoxic and endocrine effects of adjuvant chemotherapy could both contribute to the survival benefit seen in younger patients, but the relative contributions of these effects may vary by ER and immune phenotype. We hypothesize that in immune-high/ER-low cancers, the cytotoxic effect of chemotherapy may drive the benefit, whereas in immune-low/ER-intermediate cancers chemotherapy induced ovarian suppression may play a more important role. Citation Format: Tao Qing, Thomas Karn, Mariya Rozenblit, Julia Foldi, Michal Marczyk, Naing Lin Shan, Kim Blenman, uwe Holtrich, Kevin Kalinsky, Funda Meric-Bernstam, Lajos Pusztai. Molecular differences between younger versus older estrogen receptor positive/human epidermal growth factor receptor-2 negative breast cancers [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 PD9-09.

CEACAM7 expression contributes to early events of pancreatic cancer

BackgroundThe trends of pancreatic cancer (PanCa) incidence and mortality are on rising pattern, and it will be a second leading cause of cancer related deaths by 2030. Pancreatic ductal adenocarcinoma (PDAC), major form of PanCa, exhibits a grim prognosis as mortality rate is very close to the incidence rate, due to lack of early detection methods and effective therapeutic regimen. Considering this alarming unmet clinic need, our team has identified a novel oncogenic protein, carcinoembryonic antigen-related cell adhesion molecule 7 (CEACAM7), that can be useful for spotting early events of PDAC. MethodologyThis study includes bioinformatics pre-screening using publicly available cancer databases followed by molecular biology techniques in PDAC progressive cell line panel and human tissues to evaluate CEACAM7 expression in early events of pancreatic cancer. ResultsPanCa gene and protein expression analysis demonstrated the significantly higher expression of CEACAM7 in PDAC, compared to other cancers and normal pancreas. Overall survival analysis demonstrated an association between the higher expression of CEACAM7 and poor patients’ prognosis with high hazard ratio. Additionally, in a performance comparison analysis CEACAM7 outperformed S100A4 in relation to PDAC. We also observed an increase of CEACAM7 in PDAC cell line panel model. However, poorly differentiated, and normal cell lines did not show any expression. Human tissue analysis also strengthened our data by showing strong and positive IHC staining in early-stage tumors. ConclusionOur observations clearly cite that CEACAM7 can serve as a potential early diagnostic and/or prognostic marker of PDAC and may also potentiate the sensitivity of the existing biomarker panel of PDAC. However, further studies are warranted to determine its clinical significance.

Highly Pathogenic Avian Influenza H5N8 Outbreak in Backyard Chickens in Serbia

In winter 2016/2017, the highly pathogenic avian influenza virus H5N8 was detected in backyard poultry in Serbia for the first time. The second HPAI outbreak case in backyard poultry was reported in 2022, caused by subtype H5N1. This is the first study that documents the laboratory identification and pathology associated with highly pathogenic avian influenza in poultry in Serbia during the first and second introduction waves. In both cases, the diagnosis was based on real-time reverse transcriptase PCR. The most common observed lesions included subepicardial hemorrhages, congestion and hemorrhages in the lungs, and petechial hemorrhages in coelomic and epicardial adipose tissue. Histologically, the observed lesions were mostly nonpurulent encephalitis accompanied by encephalomalacia, multifocal necrosis in the spleen, pancreas, and kidneys, pulmonary congestion, and myocardial and pulmonary hemorrhages. In H5N8-infected chickens, immunohistochemical examination revealed strong positive IHC staining in the brain and lungs. Following these outbreaks, strict control measures were implemented on farms and backyard holdings to prevent the occurrence and spread of the disease. Extensive surveillance of birds for avian influenza virus did not detect any additional cases in poultry. These outbreaks highlight the importance of a rapid detection and response system in order to quickly suppress outbreaks.