Probes for HPV

Human papillomavirus (HPV)-independent primary endometrial squamous cell carcinoma (PESCC) is a rare but aggressive subtype of endometrial carcinoma for which little is known about the genomic characteristics. Traditional criteria have restricted the diagnosis of PESCC to cases without any cervical involvement. However, given that modern ancillary techniques can detect HPV and characteristic genetic alterations that should identify the more common mimics in the differential diagnosis, including endometrial endometrioid carcinoma with extensive squamous differentiation and HPV-associated primary cervical squamous cell carcinoma, those criteria may benefit from revision. To further characterize PESCC, we identified 5 cases of pure squamous cell carcinoma dominantly involving the endometrium that had the potential to be PESCC: 1 case involving only the endometrium and 4 cases with some involvement of the cervix. Clinicopathologic features were assessed and immunohistochemical analysis (p16, estrogen receptor, progesterone receptor, and p53), HPV RNA in situ hybridization (high-risk and low-risk cocktails and targeted probes for 16 and 18), and molecular studies were performed. All tumors showed aberrant/mutation-type p53 expression, were negative for estrogen receptor, progesterone receptor, and p16, and had no detectable HPV. Per whole-exome sequencing, 4 of the 5 tumors demonstrated comutations in TP53 and CDKN2A (p16). Four patients died of disease within 20 months (range, 1 to 20 mo; mean, 9 mo), and 1 patient had no evidence of disease at 38 months. PESCC represents a unique, clinically aggressive subtype of endometrial cancer with TP53 and CDKN2A comutations. This characteristic profile, which is similar to HPV-independent squamous cell carcinoma of the vulva, is distinct from endometrioid carcinoma with extensive squamous differentiation and HPV-associated primary cervical squamous cell carcinoma and can be used to distinguish PESCC from those mimics even when cervical involvement is present. Diagnostic criteria for PESCC should be relaxed to allow for cervical involvement when other pathologic features are consistent with, and ancillary techniques are supportive of classification as such.

Although both the 2014 and 2020 World Health Organization (WHO) criteria require unequivocal glandular and squamous differentiation for a diagnosis of cervical adenosquamous carcinoma (ASC), in practice, ASC diagnoses are often made in tumors that lack unequivocal squamous and/or glandular differentiation. Considering the ambiguous etiologic, morphologic, and clinical features and outcomes associated with ASCs, we sought to redefine these tumors. We reviewed slides from 59 initially diagnosed ASCs (including glassy cell carcinoma and related lesions) to confirm an ASC diagnosis only in the presence of unequivocal malignant glandular and squamous differentiation. Select cases underwent immunohistochemical profiling as well as human papillomavirus (HPV) testing by in situ hybridization. Of the 59 cases originally classified as ASCs, 34 retained their ASC diagnosis, 9 were reclassified as pure invasive stratified mucin-producing carcinomas, 10 as invasive stratified mucin-producing carcinomas with other components (such as HPV-associated mucinous, usual-type, or ASCs), and 4 as HPV-associated usual or mucinous adenocarcinomas with benign-appearing squamous metaplasia. Two glassy adenocarcinomas were reclassified as poorly differentiated HPV-associated carcinomas based on morphology and immunophenotype. There were no significant immunophenotypic differences between ASCs and pure invasive stratified mucin-producing carcinomas with regard to HPV and other markers including p16 expression. Although limited by a small sample size, survival outcomes seemed to be similar between all groups. ASCs should be diagnosed only in the presence of unequivocal malignant glandular and squamous differentiation. The 2 putative glassy cell carcinomas studied did not meet our criteria for ASC and categorizing them as such should be reconsidered.

The new World Health Organization (WHO) classification of tumours of the female genital tract (2020) divides endocervical adenocarcinoma (EAC) into human papilloma virus (HPV)-related adenocarcinoma (HPVA) and HPV-independent adenocarcinoma (HPVI) to underscore the morphological and pathogenetic correlation. It may be potentially prognostic. In this study, we appraised the new WHO classification in an independent, single institution-based EAC cohort from China to assess the clinicopathological features and prognostic value among tumour types. Our study cohort contained 402 consecutive, surgically excised EACs consisting of 298 (74.1%) HPVA, 88 (21.9%) HPVI and 16 (4%) adenocarcinomas not otherwise specified (NOS). Usual-type (55.7%) and gastric-type adenocarcinoma (GAC) (18.2%) was the most common type in HPVA and HPVI, respectively. Block p16 staining (94.7% vs 24.4%) and HPV mRNA signal (89.4% vs 0) were more common in HPVA than in HPVI (p<0.001). HPVI or GAC were more frequently associated with prognostically adverse variables including old age, large tumour size, deep invasion of the cervical wall, high tumour stage, spread of the upper genital tract, lymphovascular invasion, and mutant-type p53 expression, compared to HPVA or mucinous/usual-type HPVA, respectively (all p<0.001). In univariate survival analysis, HPVI had a worse overall survival and higher tumour recurrence compared to HPVA (p<0.05). Mucinous-type HPVA showed a worse prognosis than usual-type HPVA, but better than GAC (p<0.001). Multivariate survival analysis demonstrated that HPVI was independently associated with a worse overall survival and tumour recurrence (p<0.05) while GAC was an adverse prognostic factor independently of FIGO stage (p<0.05). Our findings validate the value of the new WHO classification in prognostic stratification and pathogenetic correlation in EAC and its subtypes.