Comparative Prognostic Value of Histology, p16, p53, HPV PCR and HPV mRNA and DNA Chromogenic In-Situ Hybridization (CISH) in Vulvar Squamous Cell Carcinomas (VSCC)
Ghassan Allo, Mei Ling Yap, Julie Cuartero, Helen Mackay, Michael Milosevic, Joan Murphy, Xiao-Jun Ma, Suzanne Kamel-Reid, Ilan Weinreb, Danny Ghazarian, Melania Pintilie, Blaise Clarke. University of Toronto, Toronto, Canada; Princess Margaret and Toronto General Hospitals, Toronto, Canada; Advanced Cell Diagnostics, Hayward, CA
Background: The incidence of VSCC is increasing.Studies suggest the presence of two histologically and molecularly distinct subsets of VSCC;one contingent on and another independent of HPV infection. HPV E6/E7 proteins can result in degradation of p53,cell cycle deregulation and abnormal expression of cyclin dependant kinase inhibitor p16. The aim of this study was to find the optimal way to determine HPV status in VSCC.
Design: Sequential VSCC from patients treated at Princess Margaret Hospital from 2000-2008 were reviewed. Histology of the in-situ and invasive tumor was assessed, classifying cases based on the presence of histologic features of HPV infection and usual dysplasia (HPV histo vs non-HPV histo).A tissue microarray was constructed. p16 and p53 immunohistochemistry,HPV E6/E7 mRNA CISH(RNAscope,Advanced Cell Diagnostics), DNA CISH(Ventana Inform HPVIII),and PCR(Roche Linear Array) were performed. Clinical data were retrieved. Survival was analyzed using Kaplan Meier curves and log rank test.
Results: We identified 119 VSCC(median age71± 16 yrs). Using various methods, the proportion of HPV+ VSCC ranged from 15-37% (table 1). p16+ VSCC were 39% of cases. Compared to HPV PCR, the HPV detection rate was 75.7%(histology), 75.7%(p16), 62.5%(p53), 66.7%(RNA CISH), and 32.4%(DNA CISH). On univariate and multivariate analysis, DNA CISH+ VSCC had a better overall survival (OS) and progression-free survival (PFS), and HPV histo, p16+, and RNA CISH+ cancers had a better PFS(table 1-2). In the 46 patients treated with radiation, HPV histo, p16+, RNA CISH+, and DNA CISH+ were associated with better PFS (p=0.018, 0.021, 0.0038, and 0.04, respectively). p53 expression was not prognostic
Conclusions: The use of histology, p16 and HPV CISH as markers of HPV active infection can predict VSCC cases with improved PFS.
|HPV histo||42/114 (36.8%)||0.84||0.63||0.48||0.011|
|p53 abnormal||70/110 (63.6%)||0.96||0.9||0.91||0.7|
|HPV DNA CISH+||17/112 (15.2%)||0.26||0.049||0.36||0.027|
|HPV RNA CISH+||34/115 (29.8%)||0.49||0.066||0.35||0.0011|
|HPV PCR+||40/118 (33.9%)||0.84||0.63||0.61||0.096|
|HPV DNA CISH+||0.23||0.045||0.33||0.061|
|HPV RNA CISH+||0.59||0.19||0.47||0.04|