Evaluation of HPV-Related Biomarkers in Anal Cytological Samples from HIV-Uninfected and HIV-Infected MSM

Abstract

Men who have sex with men (MSM) harbor the highest risk for anal carcinoma, mainly caused by Human Papillomavirus (HPV). The use of HPV-related biomarkers in the screening for this neoplasia is still debated. We assessed the association between high-risk (hr)HPV DNA, HPV16/18 DNA, hrHPV E6/E7 mRNA, and p16/Ki-67 with cytological abnormalities (any grade) and high-grade intraepithelial lesions (HSIL) in HIV-uninfected and HIV-infected MSM. Overall, 150 cytological samples in PreservCyt (Hologic), with a negative to HSIL report, were analyzed for hrHPV DNA, hrHPV E6/E7 mRNA, and p16/Ki-67 using the Linear Array (Roche), Aptima (Hologic), and CINtec® PLUS (Roche) assays. In HIV-infected MSM, positivity for all the biomarkers significantly increased with the cytological grade. In both populations, the association of hrHPV E6/E7 mRNA and p16/Ki-67 positivity with HPV16 did not differ significantly compared to hrHPVs other than HPV16. In HIV-uninfected MSM, the odds of having an HSIL increased approximately six times for the p16/Ki-67 positive cases. In HIV-infected individuals, all the biomarkers showed a significant association with HSIL, except for hrHPV DNA, with the strongest association observed for p16/Ki-67. The odds of HSIL increased almost 21 times in those positive for this biomarker. Our results encourage further investigation on the use of p16/Ki-67 dual staining in anal cancer screening for HIV-uninfected and HIV-infected MSM.

Evaluation of dual p16/Ki‐67 immunostaining on anal cytology specimens

“…Similar to other studies 18,20,21 all cases in our study with concurrent negative HPV were also negative for dual staining and therefore we believe that this is an excellent negative prognostic marker. In addition, two of the HSIL cases on biopsy were called ASCUS and LSIL on anal cytology and were positive for HR-HPV and dual staining.…”

“…When excluding unsatisfactory cases ( n = 6) in our study, a total of 32% of cases ( n = 12) were positive for dual staining which is lower in comparison to similar studies which showed about 60% overall dual stain positivity 18,21 although on par with other studies reporting about 30% positivity 17,19 . This may reflect differences in study populations.…”

“…Among ASCUS specimens, the specificity and negative predictive value of p16/Ki-67 dual staining for SIL of any grade on biopsy were 1 and 0.9 respectively, whereas the specificity and negative predictive value of HR-HPV testing for SIL of any grade on biopsy were 0.44 and 0.8 respectively. This highlights the potential utility of dual staining as an ancillary test for risk stratification and When excluding unsatisfactory cases (n = 6) in our study, a total of 32% of cases (n = 12) were positive for dual staining which is lower in comparison to similar studies which showed about 60% overall dual stain positivity 18,21 although on par with other studies reporting about 30% positivity. 17,19 This may reflect differences in study populations.…”

“…Some have focused on anal biopsies 14,15 while others on anal cytology. [16][17][18][19][20][21] High correlation between dual staining on anal cytology specimens and HR-HPV detection has been shown, 17 with high sensitivity for dual staining for AIN3 though low specificity on subsequent biopsy. 18 However, another group found low sensitivity and specificity for dual staining for the detection of biopsy proven HSIL, concluding that p16/Ki67 immunostaining did not improve the diagnostic accuracy of anal cytology.…”

“…Several studies have also examined the utility of p16 and Ki‐67 immunohistochemical staining in anal specimens. Some have focused on anal biopsies 14,15 while others on anal cytology 16–21 . High correlation between dual staining on anal cytology specimens and HR‐HPV detection has been shown, 17 with high sensitivity for dual staining for AIN3 though low specificity on subsequent biopsy 18 .…”