Probes for HPV

There is emerging evidence that vulvar squamous cell carcinoma (VSCC) can be prognostically subclassified into 3 groups based on human papillomavirus (HPV) and p53 status: HPV-associated (HPV+), HPV-independent/p53 wild-type (HPV-/p53wt), or HPV-independent/p53 abnormal (HPV-/p53abn). Our goal was to assess the feasibility of separating VSCC and its precursors into these 3 groups using p16 and p53 immunohistochemistry (IHC). A tissue microarray (TMA) containing 225 VSCC, 43 usual vulvar intraepithelial neoplasia (uVIN/HSIL), 10 verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN), and 34 differentiated VIN (dVIN), was stained for p16 and p53. Non-complementary p16 and p53 patterns were resolved by repeating p53 IHC and HPV RNA in-situ hybridization (ISH) on whole sections, and sequencing for TP53. Of 82 p16-positive VSCC, 73 (89%) had complementary p16 and p53 patterns and were classified into the HPV+ group, 4 (4.9%) had wild-type p53 staining, positive HPV ISH, and were classified into the HPV+ group, while 5 (6.1%) had p53 abnormal IHC patterns (1 null, 4 overexpression), negativity for HPV ISH and harboured TP53 mutations (1 splice-site, 4 missense); they were classified as HPV-/p53abn. Of 143 p16-negative VSCC, 142 (99.3%) had complementary p53 and p16 patterns; 115 (80.4%) HPV-/p53abn and 27 (18.9%) HPV-/p53wt. One had a basal-sparing p53 pattern, positivity for HPV ISH, and was negative for TP53 mutations; it was classified into the HPV+ category. The use of IHC also led to the following revised diagnoses: HSIL to dVIN (3/43), dVIN to vaVIN (8/34), and dVIN to HSIL (3/34). Overall, 215/225 VSCC (95.6%) could be easily classifiable into 3 groups with p16 and p53 IHC. We identified several caveats, with the major caveat being that 'double positive' p16/p53 should be classified as HPV-/p53abn, and propose an algorithm which will facilitate the application of p16 and p53 IHC to classify VSCC in pathology practice.

Papillomaviruses exclusively infect stratified epithelial tissues and cause chronic infections. To achieve this, infected cells must remain in the epithelial basal layer alongside their uninfected neighbours for years or even decades. To examine how papillomaviruses achieve this, we used the in vivo MmuPV1 model of lesion formation and persistence. During early lesion formation, an increased cell density in the basal layer, as well as a delay in the infected cells commitment to differentiation was apparent in cells expressing MmuPV1 E6/E7 RNA. Using cell culture models, keratinocytes exogenously expressing MmuPV1 E6, but not E7, recapitulated this delay in differentiation post-confluence and also grew to a significantly higher density. Cell competition assays further showed that MmuPV1 E6 expression led to a preferential persistence of the cell in the first layer, with control cells accumulating almost exclusively in the second layer. Interestingly, the disruption of MmuPV1 E6 binding to MAML1 protein abrogated these phenotypes. This suggests that the interaction between MAML1 and E6 is necessary for the lower (basal) layer persistence of MmuPV1 E6 expressing cells. Our results indicate a role for E6 in lesion establishment by facilitating the persistence of infected cells in the epithelial basal layer; a mechanism that is most likely shared by other papillomavirus types. Interruption of this interaction is predicted to impede persistent papillomavirus infection and consequently provides a novel treatment target. Importance Persistent infection with high-risk HPV types can lead to development of HPV-associated cancers, and persistent low-risk HPV infection causes problematic diseases, such as recurrent respiratory papillomatosis. The management and treatment of these conditions poses a considerable economic burden. Maintaining a reservoir of infected cells in the basal layer of the epithelium is critical for the persistence of infection in the host, and our studies using the mouse papillomavirus model suggest that E6 gene expression leads to the preferential persistence of epithelial cells in the lower layers during stratification. The E6 interaction with MAML1, a component of the Notch pathway, is required for this phenotype, and is linked to E6 effects on cell density and differentiation. These observations are likely to reflect a common E6 role that is preserved amongst papillomaviruses, and provide us with a novel therapeutic target for the treatment of recalcitrant lesions.

As the most common type of HPV-independent (HPVI) endocervical adenocarcinomas (ECAs), gastric-type endocervical adenocarcinomas (GEAs) account for approximately 10% of all ECAs Although anti-HER2 therapy has been proven effective in many cancers, it has not been utilized in ECAs including GEAs, which is at least partly due to the lack of a well-defined guideline. Limited available data regarding HER2 in GEAs and ECAs have considerable variations likely caused by variations in tumor types selection, testing methods, and scoring criteria. Here, we selected 58 GEA cases to examine the HER2 status using IHC and FISH and to investigate the prognostic value and their association with other known or potential prognostic factors. When strong complete or lateral/basolateral membranous reactivity in ≥10% tumor cells was used to define HER2 positivity, relatively high prevalence of HER2 overexpression (17.2%, 10/58) and amplification (15.5%, 9/58), as well as high IHC-FISH concordance rate (90%, 9/10) was found in GEAs. A lateral/basolateral staining pattern ('U-shaped') was observed, at least focally, in the majority of HER2-positive (3+) and equivocal (2+) tumors. Notably, considerable heterogeneity of HER2 expression was observed in HER2 positive and equivocal cases (80.0% and 83.3%, respectively). HER2 overexpression and amplification were associated with worse progression-free survival (PFS) (p=0.047 and p=0.032, respectively). PD-L1 expression was associated with worse PFS (p=0.032), while mutant type p53 demonstrated no prognostic significance. Our work laid a solid foundation for the eventual development of a future standard HER testing guideline for GEAs.