Pancreatic medullary carcinoma developed on a pancreatic intraductal papillary mucinous neoplasm with loss of MSH2 and MSH6 expression: a case report.

BACKGROUND: Pancreatic medullary carcinoma (PMC) is a rare pancreatic tumor, usually showing the presence of microsatellite instability, mostly MLH1 silencing, and a wild-type KRAS mutation status. We report here a PMC arising from a Pancreatic Intraductal Papillary Mucinous Neoplasm (IPMN), both having KRAS and TP53 mutations. CASE PRESENTATION: We report the case of a 73-year-old woman presenting with right iliac fossa pain. MRI revealed a 16 mm diameter mass in the pancreas, leading to a pancreatic duct stricture and upstream a dilatation of the distal pancreatic duct of Wirsung. A fine needle aspiration was performed, and pathology analysis revealed malignant glandular cells. The patient underwent distal pancreatectomy. Gross examination revealed an12 mm indurated white lesion, adjacent to a cystic lesion extending into the rest of the pancreatic body. Microscopically, the cystic area represented a mixed (gastric-type and pancreatobiliary-type) IPMN, involving the main and secondary pancreatic ducts with low-grade and high-grade dysplasia. In the periphery of this IPMN, a 14mm associated invasive carcinoma was observed, characterized by focal gland formation and by poorly differentiated cells with a syncytial appearance, associated with a dense lymphoplasmocytic and neutrophilic infiltrate. Immunohistochemical analyses showed loss of MSH2 and MSH6 expression. Microsatellite instability was confirmed by molecular test. Molecular analysis was performed both on the invasive carcinoma and on the high-grade dysplasia IPMN, revealing the same mutation profile with KRAS and TP53 mutations. The proposed diagnosis was mixed IPMN with associated invasive medullary carcinoma that presented loss of MSH2 and MSH6 expression. CONCLUSIONS: The present case reports for the first time, at the best of our knowledge, the coexistence of IPMN lesions and PMC, both having the same molecular alterations. It also describes the second case of PMC with microsatellite instability, MSH2 and MSH6 silenced.

Morphological predictors for microsatellite instability in urothelial carcinoma.

INTRODUCTION: Microsatellite instability occurs due to a series of mutations in the DNA pairing error repair (Mismatch repair; MMR) genes, which can affect germ cells as occurs in Lynch syndrome, whose patients are at high risk of developing multiple cancers. The loss of MMR protein is commonly determined by immunohistochemical studies. Although the relation between microsatellite instability and urothelial carcinomas has been widely studied, its evaluation is not currently performed in the analysis of urothelial carcinomas. METHODS: In this study, the microsatellite status of 139 urothelial carcinomas was analyzed and their clinicopathological characteristics were evaluated. We identified that 10.3% (13 patients) of urothelial carcinomas had loss of MMR protein expression (9 MLH1; 5 MSH2; 2 PMS2; 2 PSH6; n = 139). RESULTS: Results suggest that these tumors occur more frequently in males, are more frequently located in the bladder or ureters, and present a high tumor grade with a papillary histological pattern that does not infiltrate the lamina propria or, in the case of infiltrating tumors, that grows into perivesical tissues. CONCLUSIONS: We identified patients with the aforementioned tumor characteristics as patients with a high probability of presenting loss of MMR protein expression, and consider that only these patients should undergo further immunohistochemical and molecular techniques for proper diagnosis. Therefore, we propose that the clinicopathological characteristics found in the present study could become possible markers to determine which cases should undergo additional tests.

PD-L1, PARP1, and MMRs as potential therapeutic biomarkers for neuroendocrine cervical cancer.

OBJECTIVE: Neuroendocrine cervical cancer (NECC) is a rare cervical cancer with high aggressivity that causes poor prognosis even in the early stage. Given other neuroendocrine carcinomas and other types of cervical cancer have been proved to have expression of programmed cell death protein 1 ligand 1(PD-L1) and poly ADP-ribose polymerase-1(PARP1), we would measure and analyze these proteins in this invasive cancer. The purpose of this study is to investigate the application value of PD-1/PD-L1 and PARP1 inhibitors in NECC. METHODS: The NECC cases in our center with formalin-fixed paraffin-embedded tissue blocks were collected, and immunohistochemical (IHC) staining of PD-L1, PARP1, Mismatch repair proteins (MMRs), and P53 was performed. Chi-square test was used to analyze associations between various protein expressions. We analyzed the efficacy of immunotherapy in a recent patient with secondary recurrence after two courses of chemotherapy. RESULTS: After rigorous screening, 20 cases were finally included. Three cases did not undergo surgical treatment because of their advanced stage. Twelve (60%) developed distant metastases or relapsed within five years, and most of them within two years. The positive rate of PD-L1 and PARP1 were 70% and 75% respectively. Among all the cases, microsatellite instability (MSI) was seen in six cases (30%) and abnormal p53 expression was in 15 patients (75%). PD-L1 was associated with PARP1 expression in the MSI subgroup. The patient treated with chemotherapy + VEGF inhibitor (VEGFi) + programmed cell death protein 1(PD-1) inhibitor had an excellent improvement in clinical symptoms, tumor markers, and mass size. CONCLUSION: The IHC results of PD-L1, PARP1, and MMRs suggested that NECC was the target of immunotargeted therapy. Our case confirmed that immune checkpoint therapy was effective in patients with PD-L1 positive and MMRs loss. Considering the clinical practicability, more cases should be collected, and effective biomarkers still need to be further searched.

Mismatch repair deficiency is rare in bone and soft tissue tumors.

INTRODUCTION: There has been an increased demand for mismatch repair (MMR) status testing in sarcoma patients after the success of immune checkpoint inhibition (ICI) in MMR deficient tumors. However, data on MMR deficiency in bone and soft tissue tumors is sparse, rendering it unclear if routine screening should be applied. Hence, we aimed to study the frequency of MMR deficiency in bone and soft tissue tumors after we were prompted by two (potential) Lynch syndrome patients developing sarcomas. METHODS: Immunohistochemical expression of MLH1, PMS2, MSH2 and MSH6 was assessed on tissue micro arrays (TMAs), and included 353 bone and 539 soft tissue tumors. Molecular data was either retrieved from reports or microsatellite instability (MSI) analysis was performed. In MLH1 negative cases, additional MLH1 promoter hypermethylation analysis followed. Furthermore, a systematic literature review on MMR deficiency in bone and soft tissue tumors was conducted. RESULTS: Eight MMR deficient tumors were identified (1%), which included four leiomyosarcoma, two rhabdomyosarcoma, one malignant peripheral nerve sheath tumor and one radiation-associated sarcoma. Three patients were suspected for Lynch syndrome. Literature review revealed 30 MMR deficient sarcomas, of which 33% were undifferentiated/unclassifiable sarcomas. 57% of the patients were genetically predisposed. CONCLUSION: MMR deficiency is rare in bone and soft tissue tumors. Screening focusing on tumors with myogenic differentiation, undifferentiated/unclassifiable sarcomas and in patients with a genetic predisposition / co-occurrence of other malignancies can be helpful in identifying patients potentially eligible for ICI.

Clinicopathologic features and prognosis of synchronous and metachronous multiple primary colorectal cancer.

PURPOSE: Multiple primary colorectal cancers (MPCCs) are different from solitary colorectal cancers in many aspects, which are not well studied. The aim of this study was to clarify the clinicopathological features and prognosis of MPCCs. METHODS: The data of 64 patients with MPCCs out of 2300 patients with colorectal cancers (CRCs) from January 2009 to December 2017 were retrospectively analyzed. Stratified analysis was conducted based on subtypes and microsatellite status. RESULTS: The overall incidence of MPCC was 2.8% and the median follow-up duration was 51.5 (range 1-120) months. Metachronous CRCs (MCRCs) are more likely to appear in the right colon (p < 0.05). However, no significant differences regarding age, sex, BMI, tumor size, smoking/drinking history, TNM stage, family history of cancer, and 5-year survival rate were observed between synchronous CRC (SCRC) and MCRC. Advanced TNM stage (III) and the presence of polyps were found to be independent poor prognostic factors for MPCCs. The prevalence of mismatch repair deficiency (dMMR) in MPCCs was 28.1%. Deficient MMR is more likely to appear in younger, lighter MPCC patients with polyps (p < 0.05). Of four mismatch repair proteins, MLH-1, MSH-2, MSH-6, and PMS-2 were negative in nine, nine, five, and nine patients, respectively. The 5-year survival rate did not differ significantly between MMR-proficient (pMMR) and dMMR groups (p = 0.752). CONCLUSIONS: Synchronous CRC (SCRC) and MCRC might represent similar disease entities with different courses. Deficient MMR is more likely to appear in younger, lighter MPCC patients with polyps and it is an essential indicator for screening Lynch syndrome.

Universal Mismatch Repair Protein Screening in Upper Tract Urothelial Carcinoma.

OBJECTIVES: Universal screening of upper tract urothelial carcinoma (UTUC) for Lynch syndrome by mismatch repair (MMR) protein immunohistochemistry (IHC) has been recommended by some investigators. Herein, we assess this recommendation retrospectively by simulating its performance on a retrospective, unselected cohort of UTUCs, with comparison to the established setting of colorectal and endometrial adenocarcinoma. METHODS: We assessed for complete loss of MMR protein (MLH1, MSH2, MSH6, and PMS2) IHC in 74 consecutive cases of UTUC and then tabulated clinical and pathologic factors. MMR findings from same-institution colorectal and endometrial adenocarcinomas were tabulated for comparison. RESULTS: We observed loss of at least one MMR protein in 12% in our UTUC cohort (three MSH2/MSH6, three MSH6 only, one MLH1/PMS2, and two PMS2 only). Of these nine cases (seven males, two females, median age 67 years, five associated with colorectal adenocarcinoma), at least three (4% of the overall cohort) proved to be Lynch syndrome. Overall, MMR loss in UTUC was comparable to colorectal (11%; 50 of 471 cases) and endometrial (12%; 12 of 101 cases) adenocarcinomas. CONCLUSIONS: The rate of MMR loss observed in UTUC was comparable to that in the established setting of colorectal and endometrial adenocarcinomas, supporting universal UTUC screening at our institution and others.

Population bias in somatic measurement of microsatellite instability status.

Microsatellite instability (MSI) is a key secondary effect of a defective DNA mismatch repair mechanism resulting in incorrectly replicated microsatellites in many malignant tumors. Historically, MSI detection has been performed by fragment analysis (FA) on a panel of representative genomic markers. More recently, using next-generation sequencing (NGS) to analyze thousands of microsatellites has been shown to improve the robustness and sensitivity of MSI detection. However, NGS-based MSI tests can be prone to population biases if NGS results are aligned to a reference genome instead of patient-matched normal tissue. We observed an increased rate of false positives in patients of African ancestry with an NGS-based diagnostic for MSI status utilizing 7317 microsatellite loci. We then minimized this bias by training a modified calling model that utilized 2011 microsatellite loci. With these adjustments 100% (95% CI: 89.1% to 100%) of African ancestry patients in an independent validation test were called correctly using the updated model. This poses not only a significant technical improvement but also has an important clinical impact on directing immune checkpoint inhibitor therapy.

An Intrapatient Concordance Study of Mismatch Repair Protein Immunohistochemical Staining Patterns in Patients With Muir-Torre Syndrome.

Importance: Appropriate use criteria for Muir-Torre syndrome (MTS) screening suggest that mismatch repair protein (MMRP) immunohistochemical (IHC) testing is usually appropriate in patients with 2 or more sebaceous neoplasms (SNs). While MTS is known to be caused by a germline mutation in mismatch repair genes, data are limited as to whether individual sebaceous tumors in these patients with multiple lesions show identical MMRP IHC staining patterns. Objective: To determine concordance of MMRP IHC staining patterns in lesions of patients with MTS who have multiple SNs. Design, Setting, and Participants: This retrospective single-center case series evaluated 38 SNs in 11 patients with MTS confirmed by genetic testing for MMRP IHC staining patterns. Tumor sites were classified as either facial or extrafacial. Data were collected between January 1, 2007, and January 1, 2018. Main Outcomes and Measures: In each patient, MMRP IHC staining patterns for SNs were compared with one another to evaluate intrapatient concordance between lesions, and to the patient's known germline mutation. Results: A total of 11 patients (7 women and 4 men) with MTS, with a mean (SD) age of 59.3 (10.6) years at time of SN biopsy, were identified. There was high concordance between MMRP IHC staining results (2-4 lesions per patient) and the patient's mutation status, with 36 of 38 total lesions (95%) matching (sensitivity, 94.7%; 95% CI, 82.3%-99.4%). Extrafacial site tumors represented 16 of 38 total lesions (42%) and demonstrated 100% concordance of IHC results to germline mutation. Only 1 of 11 patients (9%) demonstrated discordant results, with both lesions in this patient occurring on a facial site. Conclusions and Relevance: In patients with known MTS, SNs present with highly concordant MMRP IHC staining profiles across multiple lesions. There is also a strong association with underlying germline mutations. A diagnosis of MTS might be supported by MMRP IHC when the pretest probability is high.

Homogeneous MMR Deficiency Throughout the Entire Tumor Mass Occurs in a Subset of Colorectal Neuroendocrine Carcinomas.

Neuroendocrine neoplasms comprise a heterogeneous group of tumors, categorized into neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) depending on tumor differentiation. NECs and high-grade NETs (G3) confer a poor prognosis, demanding novel treatment strategies such as immune checkpoint inhibition in tumors with microsatellite instability (MSI). To study any possible intratumoral heterogeneity of MSI, a tissue microarray (TMA) containing 199 NETs and 40 NECs was constructed to screen for MSI using immunohistochemistry (IHC) for the mismatch repair (MMR) proteins MLH1, PMS2, MSH2, and MSH6. Four cases suspicious for MSI were identified. Validation of MSI by repeated IHC on large sections and polymerase chain reaction (PCR)-based analysis using the "Bethesda Panel" confirmed MSI in 3 cecal NECs. One pancreatic NET G3 with MSI-compatible TMA results was MMR intact on large section IHC and microsatellite stable (MSS). The remaining 235 tumors exhibited intact MMR. Protein loss of MLH1/PMS2 was found in two and MSH6 loss in one cancer with MSI. Large section IHC on all available tumor-containing tissue blocks in NECs with MSI did not identify aberrant tumor areas with intact MMR. Our data indicate that MSI is common in colorectal NECs (3 out of 10) but highly infrequent in neuroendocrine neoplasms from many other sites. The lack of intratumoral heterogeneity of MMR deficiency suggests early development of MSI during tumorigenesis in a subset of colorectal NECs and indicates that microsatellite status obtained from small biopsies may be representative for the entire cancer mass.

[Comparison of the mismatch repair deficiency of colorectal cancers between African and European cohorts]. / Comparaison du « deficit mismatch repair ¼ des cancers colorectaux entre des cohortes africaines et européennes.

INTRODUCTION: According to European and American series, up to 20% of colorectal cancers are characterised by instability at microsatellites sites. MMR deficient colorectal cancers are predominantly found in the right colon. Although an increasing rate of colorectal cancer has been observed in many low-income countries including in West-Africa, data on epidemiology and biology of colorectal cancer in native Africans from this region are scarce. MATERIALS AND METHODS: We aimed to study the incidence of MMR deficiency in Côte d'Ivoire and to compare the data with those from a tertiary center in Belgium. Immunohistochemistry for MLH1, MSH2, MSH6 and PMS2 was performed on paraffin-embedded tissue samples from 83 colorectal cancers (46% males) operated in Abidjan and from 343 colorectal cancers (53% males) from Brussels. RESULTS: Colorectal cancer was occuring at a younger age in Côte d'Ivoire compared to Belgium (median age: 53 versus 66). MMR deficiency was detected in 11,7% of Belgian cases and in 13,3% of Ivorian cases. Whereas MMR deficient cancers in Brussels were mainly found in women (24/40 i.e. 60%), in Abidjan only 3/11 (27%) were female. Moreover, the predominant location of MMR deficient tumours was different between both series: in Brussels, mainly located in the right colon (24/40 i.e. 60%) whereas in Abidjan predominantly (10/11 i.e. 91%) in the left colon. In Brussels we observed in the majority of cases (67,5%) loss of expression of MLH1 and PMS2, in Abidjan loss of expression of MSH2 and MSH6 (54,5%). CONCLUSIONS: Our pilot study reveals differences in presentation of MMR deficient colorectal cancer between the two geographic regions suggesting differences in epidemiology and biology of colorectal cancer in native Africans.

Variable Expression of MSH6 in Endometrial Carcinomas With Intact Mismatch Repair and With MLH1 Loss Due to MLH1 Methylation.

Immunohistochemistry for mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 is an effective screen to detect individuals at risk for Lynch syndrome. College of American Pathologists guidelines stipulate that protein expression should be reported as present versus absent, as most patients with germline mutations in a mismatch repair gene have complete loss of protein expression in tumor cells. A similar approach is employed to screen for cancer patients eligible for immune checkpoint blockade. This "all or none" interpretive approach ignores substantial evidence that mismatch repair may be more finely regulated by other mechanisms. We have observed clinically that MSH6 expression is variable, even in carcinomas that are overall considered positive for MSH6 expression. A proof-of-principle study was therefore designed to more rigorously quantify the protein expression of MSH6 and its binding partner, MSH2, using image analysis applied to age-matched endometrioid grade 2 subsets that were either mismatch repair intact or MLH1-deficient due to MLH1 gene methylation. In both endometrioid groups, MSH6 expression was significantly lower than MSH2 expression. MSH6 expression increased in higher grade, mismatch repair intact serous carcinomas, but it was still significantly lower than that for MSH2. MSH2 expression was consistently high across the 3 different tumor groups. These results suggest that MSH6 expression is subject to wide fluctuations in expression, even when overall its expression is considered intact. While such fluctuations are likely not relevant for Lynch syndrome screening, they may be more impactful when considering patients eligible for immune checkpoint blockade.

p53, Mismatch Repair Protein, and POLE Abnormalities in Ovarian Clear Cell Carcinoma: An Outcome-based Clinicopathologic Analysis.

The PROMISE diagnostic algorithm, which uses p53, mismatch repair (MMR) protein immunohistochemistry, and DNA polymerase ε (POLE) exonuclease domain mutation testing, is a reliable surrogate of the molecular group in endometrial carcinoma. Its prognostic value has been validated in endometrial carcinoma and ovarian endometrioid carcinoma. Moreover, a similar prognostic grouping has been recently documented in endometrial clear cell carcinoma. Thus, we aimed to explore the role of these markers in ovarian clear cell carcinoma, another endometriosis-associated malignancy. A total of 90 cases were identified and confirmed after secondary review. Immunohistochemistry for p53, MLH1, MSH2, MSH6, and PMS2 was performed in formalin-fixed, paraffin-embedded tissue. POLE mutational analysis was performed in 47 cases. Results were correlated with clinicopathologic variables including disease-free survival (DFS), overall survival, and disease-specific survival (DSS). Endometriosis was found in 67 (74%) cases. Six (7%) tumors were p53 abnormal, 82 (91%) were p53 normal, and 2 (2%) tumors had MMR deficiency (1 MSH6 loss and 1 MSH2/6 loss; both were p53 normal). Several POLE variants of unknown significance were detected, but no pathogenic mutations. The mean follow-up period was 43 months (median: 34, range: 1 to 189). Abnormal p53 status was associated with advanced Federation of Gynecology and Obstetrics stage, lymph node metastases, DFS and DSS (P<0.05, Fisher exact test). In univariate analysis, abnormal p53 and positive lymph node status had worse DFS, whereas bilaterality, surface involvement, and advanced stage were associated with worse DFS, overall survival and DSS (P<0.05, Cox regression). On multivariate analysis, only stage retained statistical association with survival. Using a molecular-based approach designed for endometrial carcinoma, most ovarian clear cell carcinomas fall into the copy-number-low molecular subgroup. However, a small but important subset has an abnormal p53 expression (copy-number-high group). This subset is associated with adverse features including extrapelvic disease, nodal metastases, and recurrence similar to endometrial and ovarian endometrioid cancer. Thus, testing for this marker has potential prognostic significance. The role of other markers in the PROMISE algorithm remains to be elucidated, as we found a low frequency of MMR abnormalities and no pathogenic POLE mutations in our series.

Interobserver Agreement for Mismatch Repair Protein Immunohistochemistry in Endometrial and Nonserous, Nonmucinous Ovarian Carcinomas.

Immunohistochemistry (IHC) for mismatch repair (MMR) proteins is an established test to identify Lynch syndrome (LS) in patients with colorectal cancer and is being increasingly used to identify LS in women with endometrial and/or nonserous ovarian cancer (OC). We assessed interobserver agreement in the interpretation of MMR-IHC on endometrial and ovarian carcinomas. The study consisted of 73 consecutive endometrial cancers (n=48) and nonserous, nonmucinous epithelial OCs (n=25). Six pathologists from 2 cancer centers, one with and the other without, previous experience in interpreting MMR-IHC, evaluated MLH1, MSH2, MSH6, and PMS2 stains. Before the study, an experienced pathologist led a review of 9 teaching cases. A decision tool was developed as a guide in MMR-IHC interpretation. Staining was interpreted as intact, deficient, or equivocal for each protein. Interobserver agreement for the patient MMR status was categorized as "almost perfect" with κ=0.919 (95% CI, 0.863-0.976). All observers were in agreement in 66 (92%) tumors. Four of the less experienced pathologists had at least 1 discrepant interpretation. There were 6 discordant cases: 3 MMR-deficient cases and 2 MMR-intact cases by majority opinion were called equivocal by at least 1 observer, and 1 MMR-deficient case by majority opinion was interpreted as MMR intact by 1 pathologist. Only the latter case (1/73 patients, 1.4%) had an unequivocal disagreement that could affect patient management. Issues associated with discordant interpretation included heterogeneous staining, intratumoral lymphocytes, regional reduced internal control tissue staining, and scattered absent/weak staining adjacent to tumor cells with strong nuclear staining.

Additional loss of MSH2 and MSH6 expression in sporadic deficient mismatch repair colorectal cancer due to MLH1 promoter hypermethylation.

Colorectal cancer (CRC) is common with 3% of cases associated with germline mutations in the mismatch repair pathway characteristic of Lynch syndrome (LS). The UK National Institute for Health and Care Excellence recommends screening for LS in all patients newly diagnosed with CRC, irrespective of age. The Yorkshire Cancer Research Bowel Cancer Improvement Programme includes a regional LS screening service for all new diagnoses of CRC. In the first 829 cases screened, 80 cases showed deficient mismatch repair (dMMR) including four cases showing areas with loss of expression of all four mismatch repair proteins by immunohistochemistry. The cases demonstrated diffuse MLH1 loss associated with BRAF mutations and MLH1 promoter hypermethylation in keeping with sporadic dMMR, with presumed additional double hit mutations in MSH2+/-MSH6 rather than underlying LS. Recognition and accurate interpretation of this unusual phenotype is important to prevent unnecessary referrals to clinical genetics and associated patient anxiety.

Muir-Torre Syndrome: A Case Report in a Woman Without Personal Cancer History.

We report a case of a 68-year-old white woman presenting with 5 sebaceous neoplasms, ranging from sebaceous adenoma to sebaceoma on histopathology. Despite the lack of a personal cancer history, her multiple sebaceous neoplasms and a paternal history of colon cancer prompted testing her sebaceous adenomas for microsatellite instability (MSI) by immunohistochemistry. The results showed retained nuclear expressions of MLH1 and PMS2 while MSH2 and MSH6 proteins were absent. The tumor infiltrating lymphocytes expressed both MSH2 and MSH6, providing reliable internal positive controls. Having a high probability for MSI, she was found to be heterozygous for a germline point mutation in MSH2 gene, where a pathologic variant, c.1165C > T (p.Arg389*), determined by sequencing confirmed Muir-Torre syndrome (MTS). On further genetic counseling recommendations, one of her 2 sons was found to have colon cancer in the context of his MTS. In this article, we highlight and review the implications of MSI testing by both immunohistochemistry and sequencing as they relate to confirming the diagnosis of a suspected case of MTS.

Are there predictors that can determine neoadjuvant treatment responses in rectal cancer?

BACKGROUND/AIMS: This study aimed to determine a predictive bioindicator that would detect the treatment response of patients diagnosed with rectal cancer and treated with neoadjuvant chemoradiotherapy (nCRT). MATERIALS AND METHODS: The data collected from 37 patients receiving nCRT were retrospectively evaluated. The p53 score and gene instability in MLH1 and MSH2, which are among the DNA mismatch repair (MMR) genes, were evaluated using immunohistochemical methods. The neutrophils-leukocytes ratio (NLR), carcinoembryonic antigen (CEA), and carbohydrate antigen (CA) 19-9 values were obtained as hematological parameters from computer records. The pathologic analysis of the therapy response after nCRT was classified according to the modified grading system by Ryan et al. Results: The changes in the NLR, CEA, and CA19-9 values before and after treatment were statistically significant (p<0.001 and p=0.005). A near significant effect of the decrease of the CEA value in the 5th week after treatment was detected on the pathological response score (p=0.075). The p53 mutation score in those patients with any residue was higher than the total response. Overall, 89.2% of the patients exhibited MMR positivity (stability), and 10.8% of the cases with MRM negativity (instability) had a macroscopic residue. Cases with pathological total response were MRM positive. CONCLUSION: Consequently, in most of the patients treated with nCRT, the treatment caused tumor and nodal remission. In the prediction of this therapy response, hematological and genetic parameters, such as NLR, P53, MLH1, and MSH2, play a predictive role.

Minimal microsatellite shift in microsatellite instability high endometrial cancer: a significant pitfall in diagnostic interpretation.

Mismatch-repair deficiency testing plays a critical role in the identification of proband in Lynch Syndrome families and triaging patients with high stage or recurrent solid malignancies for check point inhibitor (Pembrolizumab) immunotherapy. We compared microsatellite shift patterns of microsatellite instability PCR analysis at 5 NCI recommended loci between microsatellite instability high endometrial carcinoma (n = 50) and microsatellite instability high colorectal cancer (n = 19). The endometrial cancer cohort included 45 endometrioid, 1 serous, and 4 clear cell carcinomas. Overall, 52% (26/50) of microsatellite instability high endometrial cancers showed minimal microsatellite shift (defined as a one to three nucleotide repeat shift at an involved locus) observed at least at one locus. Among microsatellite instability high endometrial cancers with minimal microsatellite shift, the frequencies at each involved locus were D2S123 (21/21, 100%), D17S250 (10/11, 89%), D5S346 (11/12, 92%), BAT25 (9/12, 80%), and BAT26 (8/21, 45%). Noticeably, 11 of the 26 cases (42%) showed only minimal shift. Among microsatellite instability high endometrial cancers with minimal microsatellite shift, 65% (17/26) had combined MLH1 and PMS2 loss, 8% (2/26) had combined MSH2 and MSH6 loss, 13% (3/26) had MSH6 loss and 15% (4/26) had loss of PMS2 by immunohistochemistry. In contrast, only 16% (3/19) had minimal microsatellite shift seen in colorectal cancer cohort with corresponding loss of MLH1/PMS2, MSH2/MSH6, or MSH6. Overall, 15% (7/50) of microsatellite instability high endometrial carcinomas showed isolated loss of MSH6 in contrast to 7% (1/15) seen in microsatellite instability high colorectal carcinomas. In conclusion, microsatellite instability high endometrial carcinomas have a significantly higher frequency of minimal microsatellite shift that coincides with a high percentage of combined loss of MLH1/PMS2. Microsatellite instability high endometrial cancers also have more frequent loss of MSH-6. Diagnostically, recognition of minimal microsatellite shift is crucial for accurate interpretation of microsatellite instability PCR data of endometrial carcinoma.

Incidence of Mismatch Repair Protein Deficiency and Associated Clinicopathologic Features in a Cohort of 104 Ovarian Endometrioid Carcinomas.

Patients with Lynch syndrome have up to a 24% risk of developing ovarian carcinoma, but universal mismatch repair (MMR) protein testing of ovarian carcinomas is not standard practice in most institutions. We reviewed 104 unselected ovarian endometrioid carcinomas (OEC) for various clinicopathologic features to determine if any are predictive of MMR loss. Immunohistochemistry for all 4 MMR proteins was performed followed by MLH1 promoter methylation analysis when indicated. Overall, patients had a mean age of 55 years and tumors averaged 12 cm. Most (72%) patients had stage I tumors, 63% were grade 1, and 30% had a synchronous stage IA endometrial endometrioid carcinoma. Peritumoral lymphocytes and intratumoral stromal inflammation were rare, but tumor-infiltrating lymphocytes averaged 47/10 high-power fields. Endometriosis was noted in 71%, adenofibromatous background in 14%, and both in 14% of tumors. Metaplastic changes were common and included squamous metaplasia (63%), clear cell change (32%), mucinous differentiation (24%), and sex cord-like elements (13%). When follow-up was available (n=99), 78% of patients were alive and well, 12% died from disease, 6% died from other causes, and 4% were alive with disease. Unmethylated, MMR-deficient OECs were identified in 7% of the cohort and included MSH2/MSH6 (n=4), MSH6 (n=2), and PMS2 (n=1). All these tumors were stage I, 71% grade 1, and 57% had a synchronous endometrial endometrioid carcinoma. Among patients in this group with follow-up (n=5), all were alive without evidence of disease (mean 150 mo). Given that no clinicopathologic features were associated with MMR deficiency on univariate analysis, this study highlights the importance of universal MMR screening in OECs.

Targeted Next-Generation Sequencing of MLH1, MSH2, and MSH6 Genes in Patients with Endometrial Carcinoma under 50 Years of Age

Background: Lynch syndrome is an inherited cancer disorder that causes an increased lifetime risk of various types of cancers. Endometrial cancer is the most common extracolonic cancer in Lynch syndrome. Guidelines recommend that patients with endometrial cancer younger than 50 years of age should be evaluated for Lynch syndrome. Molecular analysis of the mismatch repair genes and EPCAM gene is required for a definitive diagnosis of Lynch syndrome. Aims: To report the mutation analysis of mismatch repair genes using targeted next-generation sequencing in endometrial cancer diagnosed patients <50 years of age. Study Design: Retrospective cross-sectional study. Methods: Seventy-nine endometrial cancer diagnosed patients <50 years of age underwent genetic counseling. They were selected among 1094 consecutive endometrial cancer patients between 2006 and 2017. Molecular analysis of MLH1, MSH2, and MSH6 genes was performed in 79 patients by using next-generation sequencing. Deletion/duplication analysis of mismatch repair genes and EPCAM gene was also performed in 79 patients by using the multiplex ligation-dependent probe amplification method. Results: Germline testing of mismatch repair genes was performed in 79 endometrial cancer patients. Lynch syndrome was confirmed in 4 patients (5%; 4/79). A total of 14 variants (6 in MSH2, 5 in MLH1, 3 in MSH6 genes) were found in 14 patients. Four variants were assessed as pathogenic/likely pathogenic, and 10 variants were assessed as variants of uncertain significance. Conclusion: Lynch syndrome should be investigated in patients diagnosed with endometrial cancer that are less than 50 years of age due to the increased lifetime risk of developing cancer.