Mismatch Repair Protein Status Research Articles

HER2-low and Overexpression in Mucinous Ovarian Cancer: Analysis of ASCO/CAP and ToGA Immunohistochemical Scoring.

Mucinous ovarian carcinoma is an uncommon malignancy characterized by resistance to chemotherapy and poor survival in the metastatic setting. HER2 amplification is a frequent late event in carcinogenesis, yet the incidence of HER2-low in mucinous ovarian carcinoma is unknown. Further, the optimal method for determining overexpression in these tumors is not established. We sought to assess the ASCO/CAP and ToGA trial scoring methods for HER2 IHC with correlation to FISH, p53, and mismatch repair protein status and to determine the incidence of HER2-low in mucinous ovarian carcinoma. A total of 29 tumors from 23 patients were included. Immunohistochemistry for HER2, p53, MLH1, PMS2, MSH2, and MSH6 was performed. Scoring was performed according to the ASCO/CAP and ToGA trial criteria. HER2 FISH was performed and scored according to the ASCO/CAP criteria. The proportion of HER2-low, defined as 1+ or 2+ staining with negative FISH, was determined. Using ASCO/CAP, 26% demonstrated 3+ while 35% demonstrated 2+ staining. Using ToGA, 30% demonstrated 3+ while 57% demonstrated 2+ staining. By FISH, 26% were positive for HER2 amplification. Both systems captured all FISH-positive cases; the use of ASCO/CAP resulted in fewer equivocal and false-positive cases. Among HER2-negative cases, 88% were HER2-low. Aberrant p53 expression was detected in 55% of cases; mismatch repair deficiency was not identified in any cases. ASCO/CAP guidelines are accurate and resource-effective in determining HER2 overexpression in mucinous ovarian carcinoma. HER2-low is common in these tumors; further studies to determine the role of HER2-targeted therapy including antibody-drug conjugates are indicated.

Causes of death in patients operated for colorectal cancer

BackgroundColorectal cancer remains the third leading cause of cancer-related mortality in the United States. This study evaluates the causes of death in patients operated on for colorectal cancer and their determinants. MethodsAn Instructional Review Board-approved database containing patients who underwent surgical resection for colorectal cancer from 2004 to 2018 (last followed up in December 2020) in a tertiary care institution. Data on the underlying cause of death was extracted from the Registry of Vital Records and Statistics in Massachusetts. ResultsA total of 576 deaths were recorded in the database, of which 290 (50.35%) patients died of colorectal cancer. Deaths from colorectal cancer gradually decreased over time, whereas deaths from other cancers increased, and deaths from cardiovascular diseases remained stable. Patients who died from colorectal cancer were younger, died earlier in the disease course, had fewer comorbidities, higher rates of stage IV disease, rectal cancer, neoadjuvant therapy, extramural vascular invasion, perineural invasion, R0 resection, and preserved mismatch repair protein status. On multivariate analysis, age (adjusted odds ratio for 10-year increase = 0.79, 95% confidence interval 0.65–0.95), American Society of Anesthesiologists score (adjusted odds ratio = 0.64, confidence interval 0.42–0.98), stage IV disease (adjusted odds ratio = 3.02, confidence interval 1.59–5.9), neoadjuvant therapy (adjusted odds ratio = 7.91, confidence interval 2.64–28.13), extramural vascular invasion (adjusted odds ratio = 2.3, confidence interval 1.36–3.91) & time from diagnosis to death (adjusted odds ratio = 0.76, confidence interval 0.68–0.83) predicted death due to colorectal cancer versus other causes, whereas tumor location, perineural invasion, R0 resection, and mismatch repair protein status did not. ConclusionThere is a declining trend of deaths from colorectal cancer, presumably reflecting advances in colorectal cancer management strategies and better screening over time. However, younger patients disproportionately contribute to death due to colorectal cancer and need aggressive screening and management strategies.

PD-L1 Expression in Colorectal Carcinoma: A Comparison of 3 Scoring Methods in a Cohort of Jordanian Patients.

Anti-programmed death-ligand 1 (PD-L1) treatments can improve colorectal carcinoma (CRC) survival; however, there is still controversy regarding the relationship between PD-L1 expression and the outcome of immunotherapeutic treatment and survival. The discrepancies are partly caused by the lack of a unified scoring system. This retrospective, cross-sectional study evaluated PD-L1 by immunohistochemistry in 127 CRC cases and compared the 3 scoring systems used to assess PD-L1: Tumor Percentage Score (TPS), Combined Positive Score (CPS), and immune cell (IC) score. Correlations were calculated using the χ 2 test. Kaplan-Meier curves with the Log-rank test were used to measure the contribution of PD-L1 expression to survival. PD-L1-positive rate were 29.9%, 57.5%, and 55.9% based on TPS, CPS, and IC score, respectively. TPS showed a better correlation with the clinicopathologic features being significantly higher with young age, T4, and adenocarcinomas (compared with mucinous/signet ring). TPS also showed an increasing trend with higher grade, lymph node stage, and male sex, although these variables were not significantly associated with PD-L1 expression. There was no correlation between PD-L1 expression and mismatch repair protein status in the 3 scoring methods. The probability of survival was higher for PD-L1-negative cases in the first 60 months after surgery if scored by the TPS method ( P =0.058). Future efforts correlating PD-L1 status with response to treatment are needed to decide on the best scoring method to be used for making therapy decisions.

Clinicopathological characteristics of endometrial carcinomas according to DNA mismatch repair protein status

DNA mismatch repair protein deficiency (MMRd) in endometrial carcinoma is associated with the risk of Lynch syndrome and response to immune checkpoint inhibitors. It is also related to microsatellite instability and corresponds to a molecular subtype of endometrial tumor with an unclear prognosis. Here, we evaluated the clinicopathological characteristics and prognosis of 312 consecutive endometrial carcinoma cases submitted to complete surgical staging at a single institution. We compared MMRd and mismatch repair protein–proficient (MMRp) tumors and examined the effects of the MMR protein loss type (MLH1/PMS2 vs. MSH2/MSH6) and influence of L1CAM and p53 expression. The median follow-up period was 54.5 (range, 0–120.5) months. No difference was observed between MMRd [n = 166 (37.2%)] and MMRp [n = 196 (62.8%)] cases in terms of age, body mass index, FIGO stage, tumor grade, tumor size, depth of myometrial infiltration, or lymph node metastasis. More MMRd than MMRp tumors had endometrioid histology (87.9% vs. 75.5%) and despite MMRd had more lymphovascular space invasion (LVSI; 27.2% vs. 16.9%), they presented fewer recurrences and no difference in lymph node metastasis and disease-related death. Relative to those with MLH1/MSH6 loss, tumors with MSH2/MSH6 loss were diagnosed at earlier FIGO stages, were smaller, and had less ≥50% myometrial invasion, LVSI and lymph node metastasis. Outcomes, however, did not differ between these groups. L1CAM positivity and mutation-type p53 expression were more common in MMRp than in MMRd tumors and did not differ between the MLH1/PMS2 and MSH2/MSH6 loss groups. In the entire cohort, L1CAM and mutation p53 expression were associated with worse prognosis, but only non-endometrioid histology, FIGO stage III/IV, and deep myometrial infiltration were significant predictors. In the subgroup of endometrioid carcinomas, only FIGO stage III/IV was associated with poor outcomes. The risk of lymph node metastasis was associated with tumor size, non-endometrioid histology, and multifocal LVSI. For MMRd tumors, only tumor size and myometrial invasion depth were predictive of lymph node involvement. In our cohort, MMRd tumors were associated with greater recurrence-free, but not overall, survival. The precise identification of MMRd status, present in a substantial proportion of endometrial cancer cases, is a challenge to be overcome for proper patient management. MMRd status serves as a marker for Lynch syndrome, and a significant number of these tumors are high risk and candidate to immunotherapy.

Mismatch repair protein status of non-neoplastic uterine and intestinal mucosa in patients with Lynch syndrome and double somatic mismatch repair protein mutations

Mismatch repair (MMR) protein-deficient non-neoplastic colonic crypts and endometrial glands (dMMR crypts and glands) have been reported as a unique marker of underlying Lynch syndrome (LS). However, no large studies have directly compared the frequency of detection in cases with double somatic (DS) MMRmutations. We retrospectively analyzed 42 colonic resection specimens (24 LS and 18 DS) and 20 endometrial specimens (9 LS and 11 DS), including 19 hysterectomies and 1 biopsy for dMMR crypts and glands. All specimens were from patients with known primary cancers, including colonic adenocarcinomas and endometrial endometrioid carcinomas (including 2 mixed carcinomas). Four blocks of normal mucosa away from the tumor were selected from most cases, as available. MMR immunohistochemistryspecific to the primary tumor mutations was analyzed. dMMR crypts were found in 65% of LS and 0% of DS MMR-mutated colonic adenocarcinomas (P<.001). Most dMMR crypts were detected in the colon (12 of 15) compared to the ileum (3 of 15). dMMR crypts showed single and grouped losses of MMR immunohistochemical expression. dMMR glands were found in 67% of LS and 9% (1 of 11) of DS endometrial cases (P=.017). Most dMMR glands were found in the uterine wall, with 1LS and 1 DS case exhibiting dMMR glands in the lower uterine segment. Most cases exhibited multifocal and grouped dMMR glands. No morphologic atypia was identified in dMMR crypts or glands. Overall, we demonstrate that dMMR crypts and glands are highly associated with underlying LS, while being rarer in those with DS MMR mutations.

Risk factors for lymph node metastasis in patients with pT2 colon cancer in Denmark from 2016 to 2019-A nationwide cohort study.

The majority of patients with pT2 colon cancer have no lymph node metastasis (LNM). Knowledge of risk factors for LNM in pT2 colon cancer could identify patients at low risk and thereby potential candidates for local tumour excision. The aim of this work was to identify risk factors for LNM in pT2 colon cancer and describe a subgroup of low-risk patients. This is a retrospective cohort study of patients with pT2 colon cancer from a nationwide Danish colorectal cancer database. Age, tumour size, location, histological type, mismatch repair protein status and venous, lymphatic and perineural invasion were included as potential risk factors in multivariate analysis. The primary outcome was LNM. We identified 1306 patients with pT2 colon cancer. LNM was present in 244 (19%). Demographic data were comparable in patients with and without LNM, and 864 patients who had complete histological data were included for multivariate analysis. Lymphatic (OR=3.60, 95% CI 2.14-5.9), venous (OR=1.70, 95% CI 1.03-2.74) and perineural (OR=4.61, 95% CI 1.60-13.5) invasion were independent risk factors for LNM. Patients with deficient mismatch repair protein tumours had a decreased risk of LNM (OR=0.55, 95% CI 0.31-0.95). Patients with clinical Stage I colon cancer and without risk factors had a 10.5% (47/443) risk of LNM. For patients with tumours with deficient mismatch repair protein status and no risk factors, the risk was 7.9%. Lymphatic, venous and perineural invasion are significant risk factors for LNM, and we identified a subgroup of patients with a low risk of LNM.

Prognostic value of tumor budding in patients with stage II and III colon cancer: A single-institution experience.

247 Background: Tumor budding has recently been recognized as one important prognostic factor for recurrence in patients with localized colon cancer. Nevertheless, not all guidelines consider tumor budding in the decision-making process for selecting patients for adjuvant chemotherapy. We aim to assess the prognostic value of tumor budding in a cohort of patients with stage II and III colon cancer. Methods: We included patients with pathologically confirmed diagnosis of stage II and III colon cancer at Hospital Universitario La Paz and tumor budding assessment available, from October 2016 to August 2021. Tumor budding was reported following the recommendations from the 2016 International Tumour Budding Consensus Conference. Results: A total of 390 patients were included. Patients were predominantly men (55%) and had a median age of 75 (35-95). Fifty percent of the patients were stage II and 50% were localized in the right colon. Tumor budding was reported as low, intermediate, and high in 186 (48%), 110 (28%), and 94 (24%) patients, respectively. After a median follow up of 18 months, 63 recurrences and 73 deaths were observed. Time to recurrence was significantly worse for patients with high tumor budding. At 24 months, 91%, 79%, and 67% of patients with low, intermediate and high budding were recurrence-free. Median TTR was not reached in any of the three cohort (P &lt;0.001). Comparing high vs low or intermediate budding, the hazard ratio (HR) for recurrence was 0.13 [confidence interval (CI)95%: 0.05 to 0.32; P &lt; 0.001]. We performed a univariate analysis with the most relevant clinic-pathological features. T4, N2, R1, bowel obstruction or perforation, positive resection margins (R1), lymphovascular or perineural invasion, and mismatch repair protein status were found to be statistically associated with TTR and entered the multivariate analysis. T4, N2, R1 and high tumor budding (HR: 0.48 [CI95%: 0.28 to 0.84], P = 0.011) were independent prognostic factors for recurrence at the multivariate analysis. Conclusions: High tumor budding is an adverse independent prognostic factor for recurrence in patients with stage II and III colon cancer and should be acknowledge when considering adjuvant chemotherapy.

Histopathologic Features for Overall Survival in Merkel Cell Carcinoma: A Case Series with Intact Mismatch Repair Protein Expression.

In a study of Merkel cell carcinoma (MCC), a fusion transcript between MLH1 and SPATA4 was identified. This fusion has the potential to generate the inactive or dominant-negative form of the protein. Therefore, we aimed to investigate whether mismatch repair protein deficiency occurr in MCC cases or not, in addition to the overall survival association with histopathologic features. A retrospective review of 15 patients diagnosed with a biopsy-proven Merkel Cell Carcinoma between 2012 and 2019 was performed. Mismatch repair (MMR) protein expressions were evaluated by immunohistochemistry. The median follow-up time was 36 months (mean 41, range 2-103 months). Six (40%) patients died during follow-up. The overall survival (OS) at 1 year, 2 years, 3 years, and 5 years were 87%, 80%, 62%, and 53%, respectively. The patients diagnosed at < 60 years had an improved OS compared to those ≥60 years of age (p=0.016). Patients in clinical stage I had better OS than patients in clinical stage IV (p=0.011). Cases with pathological tumor stage (pT) 1 had better OS than pT3 and pT4 (p=0.045). Adjuvant radiotherapy or adjuvant radiotherapy+chemotherapy treatment improved OS compared to adjuvant chemotherapy (p=0.003). MMR protein nuclear expression was intact in 12 cases available for immunohistochemical study. To the best of our knowledge, this is the second study that preferentially investigated the mismatch repair protein status of Merkel Cell Carcinoma. No mismatch repair protein deficiency of MCC cases was identified in the current study.

Protein biomarkers in cervicovaginal lavages for detection of endometrial cancer

BackgroundRates of endometrial cancer (EC) are increasing. For a definitive diagnosis, women undergo various time-consuming and painful medical procedures, such as endometrial biopsy with or without hysteroscopy, and dilation and curettage, which may create a barrier to early detection and treatment, particularly for women with inadequate healthcare access. Thus, there is a need to develop robust EC diagnostics based on non- or minimally-invasive sampling. The objective of this study was to quantify a broad range of immuno-oncology proteins in cervicovaginal lavage (CVL) samples and investigate these proteins as predictive diagnostic biomarkers for EC.MethodsOne hundred ninety-two women undergoing hysterectomy for benign or malignant indications were enrolled in this cross-sectional study. Classification of women to four disease groups: benign conditions (n = 108), endometrial hyperplasia (n = 18), low-grade endometrioid carcinoma (n = 53) and other EC subtypes (n = 13) was based on histopathology of biopsy samples collected after the surgery. CVL samples were collected in the operating room during the standard-of-care hysterectomy procedure. Concentrations of 72 proteins in CVL samples were evaluated using multiplex immunoassays. Global protein profiles were assessed using principal component and hierarchical clustering analyses. The relationships between protein levels and disease groups and disease severity were determined using Spearman correlation, univariate and multivariate receiver operating characteristics, and logistic regression analyses.ResultsWomen with EC and benign conditions exhibited distinctive cervicovaginal protein profiles. Several proteins in CVL samples (e.g., an immune checkpoint protein, TIM-3, growth factors, VEGF, TGF-α, and an anti-inflammatory cytokine, IL-10) discriminated EC from benign conditions, particularly, when tested in combinations with CA19–9, CA125, eotaxin, G-CSF, IL-6, MCP-1, MDC, MCP-3 and TRAIL (sensitivity of 86.1% and specificity of 87.9%). Furthermore, specific biomarkers (e.g., TIM-3, VEGF, TGF-α, TRAIL, MCP-3, IL-15, PD-L2, SCF) associated with histopathological tumor characteristics, including histological type and grade, tumor size, presence and depth of myometrial invasion or mismatch repair protein status, implying their potential utility for disease prognosis or monitoring therapies.ConclusionsThis proof-of-principle study demonstrated that cervicovaginal sampling coupled with multiplex immunoassay technology can offer a minimally to non-invasive method for EC detection.

The prognostic impact of the immune microenvironment in small-cell neuroendocrine carcinoma of the uterine cervix: PD-L1 and immune cell subtypes

BackgroundWe investigate the correlation between programmed cell death-ligand 1 (PD-L1) and tumor-associated immune cell (TAIC) density in small-cell neuroendocrine carcinoma of the uterine cervix (SCNEC) and their correlation with clinicopathologic features.MethodsPD-L1 and mismatch repair protein (MMR) expression in cancer cells and the density of TAIC were evaluated by immunohistochemistry in 89 SCNEC patients. The combined positive score (CPS), tumor proportion score (TPS), and immune cell score (ICS) of PD-L1 were measured, along with their correlation with clinicopathologic features in SCNEC patients using statistical analyses.ResultsCPS of PD-L1 ≥ 1 was seen in 68.5% of patients, positive TPS and ICS of PD-L1 were detected in 59.6% and 33.7% of patients, respectively. PD-L1CPS was higher in tumor-infiltrating immune cells (r = 0.387, p = 0.001) and positively correlated with programmed cell death-1 and forkhead box P3 + regulatory T cell (FOXP3 + Treg) infiltration (r = 0.443, p < 0.001; r = 0.532, p < 0.001). There was no statistical correlation between PD-L1 and MMR status. PD-L1CPS and PD-L1ICS positivity were independent prognostic factors, correlating with a favorable survival (HR (95%CI) = 0.363(0.139–0.950), p = 0.039 and HR (95% CI) = 0.199(0.050–0.802), p = 0.023, respectively). PD-L1ICS positivity was an independent indicator of recurrence in SCNEC patients and associated with better disease-free survival (HR (95% CI) = 0.124(0.036–0425), p = 0.001). TAIC and MMR levels had no statistical impact on survival results.ConclusionsPD-L1 positivity was seen in over half of SCNEC tumors. It may work synergistically with FOXP3 + Treg and other infiltrating immune cells to support an adaptive immune response. PD-L1 positivity may be a favorable prognostic factor in SCNEC.

The association between the tumor immune microenvironments and clinical outcome in low-grade, early-stage endometrial cancer patients.

Endometrial tumors show substantial heterogeneity in their immune microenvironment. This heterogeneity could be used to improve the accuracy of current outcome prediction tools. We assessed the immune microenvironment of 235 patients diagnosed with low-grade, early-stage endometrial cancer. Multiplex quantitative immunofluorescence was carried out to measure CD8, CD68, FOXP3, PD-1, and PD-L1 markers, as well as cytokeratin (CK), on tissue microarrays. Clustering results revealed five robust immune response patterns, each associated with specific immune populations, cell phenotypes, and cell spatial clustering. Most samples (69%) belonged to the immune-desert subtype, characterized by low immune cell densities. Tumor-infiltrating lymphocyte (TIL)-rich samples (4%) displayed high CD8+ T-cell infiltration, as well as a high percentage of CD8/PD-1+ cells. Immune-exclusion samples (19%) displayed the lowest CD8+ infiltration combined with high PD-L1 expression levels in CK+ tumor cells. In addition, they demonstrated high tumor cell spatial clustering as well as increased spatial proximity of CD8+ /PD-1+ and CK/PD-L1+ cells. FOXP3 and macrophage-rich phenotypes (3% and 4% of total samples) displayed relatively high levels of FOXP3+ regulatory T-cells and CD68+ macrophages, respectively. These phenotypes correlated with clinical outcomes, with immune-exclusion tumors showing an association with tumor relapse. When compared with prediction models built using routine pathological variables, models optimized with immune variables showed increased outcome prediction capacity (AUC = 0.89 versus 0.78) and stratification potential. The improved prediction capacity was independent of mismatch repair protein status and adjuvant radiotherapy treatment. Further, immunofluorescence results could be partially recapitulated using single-marker immunohistochemistry (IHC) performed on whole tissue sections. TIL-rich tumors demonstrated increased CD8+ T-cells by IHC, while immune-exclusion tumors displayed a lack of CD8+ T-cells and frequent expression of PD-L1 in tumor cells. Our results demonstrate the capability of the immune microenvironment to improve standard prediction tools in low-grade, early-stage endometrial carcinomas. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

CT-based radiomic nomogram for preoperative prediction of DNA mismatch repair deficiency in gastric cancer.

BackgroundDNA mismatch repair (MMR) deficiency has attracted considerable attention as a predictor of the immunotherapy efficacy of solid tumors, including gastric cancer. We aimed to develop and validate a computed tomography (CT)-based radiomic nomogram for the preoperative prediction of MMR deficiency in gastric cancer (GC).MethodsIn this retrospective analysis, 225 and 91 GC patients from two distinct hospital cohorts were included. Cohort 1 was randomly divided into a training cohort (n = 176) and an internal validation cohort (n = 76), whereas cohort 2 was considered an external validation cohort. Based on repeatable radiomic features, a radiomic signature was constructed using the least absolute shrinkage and selection operator (LASSO) regression analysis. We employed multivariable logistic regression analysis to build a radiomics-based model based on radiomic features and preoperative clinical characteristics. Furthermore, this prediction model was presented as a radiomic nomogram, which was evaluated in the training, internal validation, and external validation cohorts.ResultsThe radiomic signature composed of 15 robust features showed a significant association with MMR protein status in the training, internal validation, and external validation cohorts (both P-values <0.001). A radiomic nomogram incorporating a radiomic signature and two clinical characteristics (age and CT-reported N stage) represented good discrimination in the training cohort with an AUC of 0.902 (95% CI: 0.853–0.951), in the internal validation cohort with an AUC of 0.972 (95% CI: 0.945–1.000) and in the external validation cohort with an AUC of 0.891 (95% CI: 0.825–0.958).ConclusionThe CT-based radiomic nomogram showed good performance for preoperative prediction of MMR protein status in GC. Furthermore, this model was a noninvasive tool to predict MMR protein status and guide neoadjuvant therapy.

PRAME Expression in Endometrioid and Serous Endometrial Carcinoma: A Potential Immunotherapeutic Target and Possible Diagnostic Pitfall.

Preferentially expressed antigen in melanoma (PRAME) is a cancer testes antigen initially employed as a diagnostic marker for melanoma. Although negative in most normal tissues, its expression has been reported in benign endometrial glands. Additionally, PRAME expression has been identified in a growing list of solid and hematologic malignancies and is of interest as a predictive biomarker, as cancer vaccination strategies and adoptive T-cell transfer targeting this molecule are under clinical investigation; additionally, PRAME may identify candidates for retinoid therapy. However, expression of PRAME has not been well-studied in endometrial cancers. We herein evaluate PRAME expression in endometrial carcinomas to better characterize its limitations as a diagnostic melanoma marker as well as its potential as a predictive biomarker in endometrial carcinomas. PRAME expression was evaluated in 256 endometrioid (n=235) and serous (n=21) endometrial carcinomas via tissue microarray. In all, 89% (227/256) demonstrated some degree of nuclear PRAME expression, including 88% (207/235) of endometrioid carcinomas and 95% (20/21) of serous carcinomas. Diffuse (>50%) expression was observed in 70% (179/256) of all cases, including 69% (163/235) of endometrioid carcinomas and 76% (16/21) of serous carcinomas. There was no association between degree of expression and grade, mismatch repair protein status, or stage. The widespread expression of PRAME in endometrial carcinomas suggests this marker should not be interpreted as specific for melanoma in this context. However PRAME may have utility as a predictive biomarker in endometrial cancer, and expansion of testing of PRAME-based therapies to endometrioid and serous endometrial carcinomas may lead to new therapeutic options for these endometrial cancer subtypes.

Clinicopathologic significance of DNA mismatch repair protein status in endometrial cancer

ObjectiveThe prognostic implications of DNA mismatch repair protein (MMRP) have not been determined in endometrial cancer. Therefore, in this study, we aimed to evaluate the clinicopathologic characteristics of DNA MMRP deficiency in endometrial cancer. Materials and methodsWe examined the MMRP status of 206 patients with endometrial carcinomas, using immunohistochemistry, and analyzed their clinicopathologic factors and survival outcomes stratified by MMRP status using the Kaplan–Meier method and Cox regression analysis. ResultsForty-three cases were deficient for at least one MMRP (20.9%). Loss of MLH1 was the most common (13.1%), followed by MSH6 (7.8%). MMRP deficiency was significantly associated with lympho-vascular space invasion, deep myometrial invasion, and adjuvant treatment (P = 0.032, 0.041, and 0.047, respectively). MMRP-deficient patients had a better overall survival (OS), particularly at advanced cancer stages (III/IV) (100% vs. 73.7%, P = 0.170) or if they had received adjuvant treatment (100% vs. 86.7%, P = 0.087). ConclusionAlthough MMRP deficiency was associated with unfavorable prognostic risk factors in endometrial cancer, we found a trend in favor of OS in MMRP-deficient patients. More studies are needed to confirm its prognostic implication.

Defining hereditary upper tract urothelial carcinoma: Implications for genetic testing and clinical management.

523 Background: Despite being a rare cancer, upper tract urothelial carcinoma (UTUC) is the third most common core cancer associated with Lynch syndrome (LS) after colorectal and endometrial cancers. Yet, there is no established guideline to identify patients with UTUC who are at risk of carrying germline mutations in LS-associated genes. The objective of this study is to define selection criteria for patients with UTUC for LS screening. Methods: We retrospectively identified patients with UTUC who underwent germline sequencing of ≥77 cancer susceptibility genes using next generation sequencing (NGS) as part of a prospective matched tumor-normal genomic profiling initiative from 04/2015 to 04/2021. Mismatch repair protein status was evaluated by immunohistochemical (IHC) staining for MMR genes MSH2, MSH6, MLH1, and PMS2. Microsatellite instability (MSI) status was determined using NGS. Diagnostic performance of clinical and tumor-based screening criteria was assessed by the presence of germline pathogenic/likely pathogenic variants (PGVs) in MMR genes. Results: A total of 232 patients with UTUC underwent germline testing; median age of diagnosis was 67 years (interquartile range 59 – 73). Of these patients, 70% were male, 43% had UTUC diagnosed before the age of 65, 85% had high grade UTUC,12% had bilateral UTUC, 11% had metastasis at diagnosis, 10% and 31% had personal and family history of LS-associated cancers, respectively. PGVs in moderate or high-penetrance genes were identified in 31 (13%) patients including 6 (3%) in BRCA1/ 2 and 21 (9%) in MMR genes (13 MSH2, 4 MSH6, 4 MLH1). A total of 10/21 (48%) patients with MMR PGVs developed UTUC as their first cancer diagnosis. Of patients with MMR PVGs, 15/16 (94%) had MMR-deficient tumors and 12/18 (67%) had MSI-high tumors. Personal and family history of LS core cancers (p &lt; 0.001), age of diagnosis &lt; 65 (p = 0.008), MSI-high (p &lt; 0.001), and MMR-deficiency (p &lt; 0.001) were associated with MMR carrier status. Female gender (p = 0.7), HG UTUC (p = 0.5), and bilateral UTUC (p = 0.7) were not associated with MMR PGVs. Current NCCN genetic referral criteria for Lynch syndrome has high specificity in identifying patients with LS (100%) but missed 11/21 (52%) patients with UTUC and MMR PGVs. Conclusions: Current genetic referral guidelines for Lynch syndrome may miss a significant portion of patients with LS-associated UTUC. UTUC tumor should be investigated for MMR protein and MSI status with IHC or next generation sequencing methods to augment LS-screening of patients with UTUC and inform systemic treatment selection.

Combined histopathological risk score using TP53 protein expression, CD8+ T cell density and intratumoral budding is an independent predictor of neoadjuvant therapy response in rectal adenocarcinoma.

Neoadjuvant therapy is the recommended treatment for locally advanced rectal adenocarcinoma; however, there remains significant variability in response to therapy. Tumour protein 53 (TP53) has been associated with therapy response and prognosis with conflicting data. Recently, we demonstrated that immune cell density and intratumoral budding (ITB) are predictive factors in rectal cancer. We investigated the predictive value of TP53 immunohistochemistry with CD8+ T cell density and ITB on pretreatment biopsies of rectal adenocarcinoma for response to neoadjuvant therapy. Pretreatment biopsies of rectal adenocarcinoma from 117 patients with neoadjuvant therapy were analysed for TP53 expression by immunohistochemistry, ITB, CD8+ T cell density and mismatch repair protein (MMR) status. Most rectal adenocarcinomas displayed aberrant TP53 expression (86 of 117, 74%). Compared to wild-type TP53, aberrant TP53 expression was associated with proficient MMR status (P=0.003) and low CD8+ T cell density (P=0.001). Aberrant TP53 was significantly associated with a partial to poor response to neoadjuvant therapy [odds ratio (OR)=2.42, 95% confidence interval (CI)=1.04-5.62, P=0.04]. A combined histopathological risk score (HRS) was created using CD8+ T cell density, ITB and TP53 expression. Patients were separated into low (none to one factor) and high (two to three factors) HRS categories. In the multivariable model, patients with a high HRS were 3.25-fold more likely to have a partial or poor response to neoadjuvant therapy (95% CI=1.48-7.11, P=0.003). Our study demonstrates that aberrant TP53 expression, high ITB and low CD8+ T cell density in pretreatment biopsies can help predict response to neoadjuvant therapy. These biomarkers may be helpful in identifying patients at risk for therapy resistance.

Effect of mismatch repair protein status on outcomes in high intermediate risk endometrial cancer

<h3>Objectives:</h3> To compare recurrence rates between patients with mismatch repair proficient (pMMR) and MMR deficient (dMMR) high intermediate risk (HIR) endometrial cancer <h3>Methods:</h3> Adult women with HIR endometrial cancer diagnosed between January 1, 2016, and December 31, 2018, were identified from UC San Diego and Kaiser Southern California. Patient and disease characteristics were collected by chart review. Cases were limited to those who underwent hysterectomy with endometrioid histology and stage 1 disease. HIR disease was defined as the presence of three risk factors if age < 50 years, two risk factors if age ≥50 and <70 years, and one risk factor if age ≥70 years. Risk factors included tumor grade 2 or 3, the presence of lymphovascular space invasion (LVSI), and ≥50% myometrial invasion as outlined in GOG protocol 249. Categorical variables were compared using Chi-square tests, and continuous variables were compared using Student's t-test. The Kaplan-Meier method was used to evaluate time to recurrence. Assuming a two-sided alpha error of 0.05, power calculation identified a sample size of 174 would be needed to detect a 0.15 difference in recurrence rates between cohorts with 80% power. <h3>Results:</h3> Two hundred forty-four patients with HIR endometrial cancer were identified during the study period. One hundred fifty-eight patients (65%) were pMMR by immunohistochemical staining, and 86 patients (35%) were dMMR. There were no differences in mean age, mean body mass index (BMI), race, grade, mean follow-up time, or type of adjuvant treatment received between the pMMR versus dMMR cohorts. In total, 40 (16%) patients experienced cancer recurrence, and there were 11 (4.5%) cancer-related deaths during the study period. There was no statistically significant difference in recurrence rates between the pMMR and dMMR cohorts (15% versus 19%, p=0.49). The lack of association between MMR status and recurrence persisted after controlling for depth of myometrial invasion and LVSI in logistic regression multivariable analysis. pMMR tumors were more likely to exhibit ≥50% myometrial invasion than patients with dMMR tumors (p=0.03). dMMR tumors were significantly more likely to exhibit LVSI than pMMR tumors (p<0.001). There was no statistically significant association between the type of adjuvant treatment received and MMR status among those who recurred (p=0.58). Among patients who recurred, site of first recurrence (local vs distant) was not associated with MMR status (p=.90). The mean time to recurrence was 531 days in the pMMR cohort (n=24) and 473 days in the dMMR cohort (n=16), which was not significantly different (p=0.28). <h3>Conclusions:</h3> Our analysis represents one of the largest recurrence rate analyses of HIR endometrial cancer as stratified by MMR status. Although our pMMR and dMMR patient cohorts with HIR did not differ with respect to patient characteristics, dMMR tumors were significantly more likely to have <50% myometrial invasion and to exhibit LVSI. Despite these differences, we observed no difference in recurrence rates or time to recurrence between the two groups, which is in contrast to previously published reports of better prognosis among patients with pMMR tumors. Further study is ongoing to evaluate the effect of mismatch repair status on treatment selection and patient outcomes.

Colonic epithelial cathelicidin (LL-37) expression intensity is associated with progression of colorectal cancer and presence of CD8+ T cell infiltrate.

Colorectal cancer (CRC) remains a leading cause of cancer mortality. Here, we define the colonic epithelial expression of cathelicidin (LL‐37) in CRC. Cathelicidin exerts pleotropic effects including anti‐microbial and immunoregulatory functions. Genetic knockout of cathelicidin led to increased size and number of colorectal tumours in the azoxymethane‐induced murine model of CRC. We aimed to translate this to human disease. The expression of LL‐37 in a large (n = 650) fully characterised cohort of treatment‐naïve primary human colorectal tumours and 50 matched normal mucosa samples with associated clinical and pathological data (patient age, gender, tumour site, tumour stage [UICC], presence or absence of extra‐mural vascular invasion, tumour differentiation, mismatch repair protein status, and survival to 18 years) was assessed by immunohistochemistry. The biological consequences of LL‐37 expression on the epithelial barrier and immune cell phenotype were assessed using targeted quantitative PCR gene expression of epithelial permeability (CLDN2, CLDN4, OCLN, CDH1, and TJP1) and cytokine (IL‐1β, IL‐18, IL‐33, IL‐10, IL‐22, and IL‐27) genes in a human colon organoid model, and CD3+, CD4+, and CD8+ lymphocyte phenotyping by immunohistochemistry, respectively. Our data reveal that loss of cathelicidin is associated with human CRC progression, with a switch in expression intensity an early feature of CRC. LL‐37 expression intensity is associated with CD8+ T cell infiltrate, influenced by tumour characteristics including mismatch repair protein status. There was no effect on epithelial barrier gene expression. These data offer novel insights into the contribution of LL‐37 to the pathogenesis of CRC and as a therapeutic molecule.

PD-L1 Expression Is an Independent Marker for Lymph Node Metastasis in Middle Eastern Endometrial Cancer.

Programmed death ligand 1 (PD-L1) expression in endometrial cancer (EC) tumor cells have been reported in several studies with inconsistent results. Furthermore, there is scarcity of data on the prevalence and prognostic significance of PD-L1 expression in EC from Middle Eastern ethnicity. We aimed to assess PD-L1 expression in a large cohort of Middle Eastern EC and to correlate this with clinico-pathological factors, as well as mismatch repair (MMR) protein status and patients’ outcome. PD-L1 expression was investigated using immunohistochemistry on tissue microarray in an unselected cohort of 440 EC. Kaplan–Meier and logistic regression analysis were used to compare the outcome and prognostic factors. PD-L1 expression in tumor tissue was detected in 18.9% (83/440) EC cases with no impact on survival. When stratified for MMR protein status, PD-L1 expression was similar for both MMR deficient and MMR proficient ECs. However, the expression of PD-L1 in tumor cells was significantly associated with type II (non-endometrioid) histology (p = 0.0005) and lymph node metastasis (p = 0.0172). Multivariate analysis showed PD-L1 expression to be an independent risk factor for lymph node metastasis (odds ratio: 2.94; 95% CI: 1.26–6.84; p = 0.0123). In conclusion, PD-L1 was strongly associated with non-endometrioid EC and was an independent prognostic marker of lymph node metastasis.

Implication of expression of MMR proteins and clinicopathological characteristics in gastric cancer

Introduction Microsatellite instability (MSI), referred to as variations at microsatellite loci, at mismatch repair (MMR) genes leads to the formation of an aberrant MMR system that fails to rectify errors occurring during DNA replication. MMR deficiency can be assessed by immunohistochemical analysis of the expression of mismatch repair proteins in the target tissues. Methods We investigated the expression of four key MMR proteins (MLH1, MSH2, MSH6, and PMS2) in formalin-fixed paraffin-embedded (FFPE) tumor and normal tissues obtained from thirty gastric cancer (GC) patients. The association of clinicopathological features with MMR status was also analyzed. Results A total of 12 (40%) GC patients exhibited loss of expression of MMR proteins, including loss of MLH1 and PMS2 in 3 cases and loss of MSH2 and MSH6 in 4 cases. Univariate analysis showed an association of loss of MMR protein expression with moderately differentiated GC. However, there was no statistically significant association between loss of MMR protein expression with gender, tumor location, depth of invasion, lymph node metastasis, WHO classification, lympho-vascular invasion, and infection with H. pylori. Conclusion Our results implicate the role of mismatch repair proteins in gastric tumorigenesis. The MMR protein status is an important aspect of tumorigenesis and can be prescribed for the screening of GC.