Practical guidance for mismatch repair-deficiency testing in endometrial cancer.

Background: Mismatch repair (MMR)-deficiency analysis is increasingly recommended for all endometrial cancers, as it identifies Lynch syndrome patients, and is emerging as a prognostic classifier to guide adjuvant treatment. The aim of this study was to define the optimal approach for MMR-deficiency testing and to clarify discrepancies between microsatellite instability (MSI) analysis and immunohistochemical (IHC) analysis of MMR protein expression. Patients and methods: Six hundred ninety- six endometrial cancers were analyzed for MSI (pentaplex panel) and MMR protein expression (IHC). Agreement between methodologies was calculated using Cohen's Kappa. MLH1 promoter hypermethylation, dinucleotide microsatellite markers and somatic MMR and POLE exonuclease domain (EDM) gene variants (using next-generation/Sanger sequencing) were analyzed in discordant cases. Results: MSI was found in 180 patients. Complete loss of expression of one or more MMR proteins was observed in 196 cases. A PMS2- and MSH6-antibody panel detected all cases with loss of MMR protein expression. The results of MSI and MMR protein expression were concordant in 655/696 cases (kappa = 0.854, P < 0.001). Ambiguous cases (n = 41, 6%) included: subclonal loss of MMR protein expression (n = 18), microsatellite stable or MSI-low cases with loss of MMR protein expression (n = 20), and MSI-low or MSI-high cases with retained MMR protein expression (n = 3). Most of these cases could be explained by MLH1 promoter hypermethylation. Five of seven cases with solitary loss of PMS2 or MSH6 protein expression carried somatic gene variants. Two MSI-high cases with retained MMR protein expression carried a POLE-EDM variant. Conclusion: MSI and IHC analysis are highly concordant in endometrial cancer. This holds true for cases with subclonal loss of MMR protein expression. Discordant MMR-proficient/MSI-high cases (<1%), may be explained by POLE-EDM variants.

Alterations in classical and nonclassical HLA expression in recurrent and progressive HPV-induced usual vulvar intraepithelial neoplasia and implications for immunotherapy.

Immunotherapy of usual vulvar intraepithelial neoplasia (uVIN) is promising; however, many patients still fail to show clinical responses, which could be explained by an immune escape through alterations in human leukocyte antigen (HLA) expression. Therefore, we analyzed a cohort of patients with a primary (n = 43) and subsequent recurrent uVIN lesion (n = 20), vaccine-treated uVIN patients (n = 12), patients with human papillomavirus (HPV)-induced vulvar carcinoma (n = 21) and healthy controls (n = 26) for the expression of classical HLA-class I/II and nonclassical HLA-E/-G and MHC class I chain-related molecule A (MICA). HLA-class I was downregulated in 70% of uVIN patients, including patients with a clinical response to immunotherapy. Downregulation of HLA-class I is probably reversible, as only 15% of the uVIN cases displayed loss of heterozygosity (LOH) and HLA-class I could be upregulated in uVIN keratinocyte cultures by interferon γ. HLA-class I downregulation is more frequently associated with LOH in vulvar carcinomas (25-55.5%). HLA-class II was found to be focally expressed in 65% of uVIN patients. Of the nonclassical molecules, MICA was downregulated in 80% of uVIN whereas HLA-E and -G were expressed in a minority of cases. Their expression was more prominent in vulvar carcinoma. No differences were found between the alterations observed in paired primary and recurrent uVIN. Importantly, downregulation of HLA-B/C in primary uVIN lesions was associated with the development of recurrences and progression to cancer. We conclude that downregulation of HLA is frequently observed in premalignant HPV-induced lesions, including clinical responders to immunotherapy, and is associated with worse clinical outcome. However, in the majority of cases downregulation may still be reversible.

Spindle cell morphology is related to poor prognosis in vulvar squamous cell carcinoma.

BACKGROUND: Vulvar cancer is the fourth most common gynaecological malignancy, with an annual incidence of 2 out of 100,000 women. Although most cases of early stage vulvar cancer have a good prognosis, recurrence and rapid tumour progression can occur. We investigated the prevalence of spindle cell morphology in vulvar cancer and its association with survival. METHODS: This retrospective cohort study included 108 patients with primary vulvar squamous cell carcinoma who were treated at the Leiden University Medical Center during 2000-2009. Paraffin-embedded tissue was examined for the presence of spindle cell morphology. Survival and histology data were compared between cases with spindle and without spindle cell morphology. RESULTS: Twenty-two (20%) tumours showed spindle cells infiltrating the stromal tissue. All spindle cell tumours were human papillomavirus (HPV) negative. Spindle cell morphology was strongly associated with poor prognosis and with a high risk of lymph node involvement at the time of diagnosis (relative risk 2.26 (95% CI 1.47-3.47)). Five-year disease-specific survival was lower in patients with vs without spindle cell morphology (45.2% vs 79.7%, respectively; P=0.00057). CONCLUSION: Vulvar spindle cell morphology occurs frequently and seems to develop through the non-HPV pathway. It is associated with a worse prognosis than conventional vulvar squamous cell carcinoma.