Evaluation of p16INK4a immunostaining for the detection of high-grade changes in cervical cytology.

Since its introduction in Australia in 2007, the human papillomavirus (HPV) vaccine has led to a markedly lower prevalence of vaccine targeted HPV genotype infections as well as HPV disease including genital warts and histologically confirmed high-grade (HG) cervical abnormalities. To increase the ability to identify abnormal cells in lower prevalence, adjunct markers can be incorporated to improve the sensitivity and specificity of cytology test. One such marker is p16(p16), which is detectable in cells expressing the E7 oncogene encoded by high-risk HPVs (HR-HPV). In this study, the sensitivity and specificity of p16 immunostaining in detection of underlying HG lesions was evaluated in a cohort of 454 women undergoing surgical treatment for biopsy proven cervical dysplasia. Overall, p16 positive cells were detected in 321 (71%) of cytology preparations evaluated. Comparison of p16 staining on cytological preparations to histology diagnosis available on 212 patients, showed 26 (54%), 41 (78%) and 80 (90%) of cytology preparations to be p16 positive in women with CIN1, CIN2 and CIN3, respectively (p < 0.005). HPV16 and 18 were the most prevalent genotypes in HG lesions and were highly correlated with p16 staining. p16 staining provides an additional marker which can assist in better detecting underlying HG lesion in cytology smears with low disease prevalence.

Investigating a cluster of vulvar cancers in young women: distribution of human papillomavirus and HPV-16 variants in vulvar dysplastic or neoplastic biopsies.

BACKGROUND: A high incidence of vulvar cancer, and its precursor lesion, high-grade vulvar intraepithelial neoplasia (VIN) has been identified in young Indigenous women living in the Arnhem Land region of the Northern Territory (NT) of Australia. This clustering is restricted to women aged <50 years, suggesting that oncogenic human papillomavirus (HPV) is a key causal factor. This study compared the HPV genotype prevalence, HPV-16 variant distribution and p16(INK4a)expression in stored vulvar cancer and high-grade VIN biopsy specimens from women residing in Arnhem Land, with specimens taken from Indigenous and non-Indigenous women in other regions of NT where there is no observed increase in vulvar cancer incidence. METHODS: Twenty high-grade VIN and 10 invasive cancer biopsies were assessed from Arnhem Land along with 24 high-grade VIN and 10 invasive cancer biopsies from other regions of NT. RESULTS: Biopsies from Arnhem Land were similar to those from other regions in the detection of high-risk (HR) or possible HR HPV (VIN: 95% and 84% respectively for Arnhem Land and other regions, P=0.356; invasive cancer: 100% and 80%, P=0.473), HPV-16 (VIN: 60% and 80%, P=0.364; invasive cancer: 70% and 70%, P=1.0) and p16(INK4a) expression (VIN: 90% and 84%, P=0.673; invasive cancer: 100% and 80%, P=0.474). All HPV-16 variants were of the European prototype. CONCLUSION: Comparison of biopsies revealed no significant difference in the frequency of oncogenic HPVs or HPV-16 variant types between Arnhem Land and other regions, suggesting another cofactor in this cluster.

Investigating a cluster of vulvar cancer in young women: a cross-sectional study of genital human papillomavirus prevalence.

BACKGROUND: Vulvar cancer is a relatively rare malignancy, which occurs most often in postmenopausal women. We have previously identified a geographic cluster of vulvar cancer in young Indigenous women living in remote communities in the Arnhem Land region of Australia. In this population, we investigated the prevalence of oncogenic human papillomavirus (HPV) infection in anogenital samples (vulvar/vaginal/perianal area and cervix) and compared the overall, type-specific and multiple infection prevalence between sites. METHODS: A cross-sectional survey of 551 Indigenous women aged 18-60 years was undertaken in 9 Arnhem Land communities. Women were consented for HPV detection and genotyping collected by a combined vulvar/vaginal/perianal (VVP) sweep swab and a separate PreservCyt endocervical sample collected during Pap cytology screening. HPV DNA testing was undertaken using PCR with broad spectrum L1 consensus PGMY09/11 primers with genotyping of positive samples by Roche Linear Array. The primary outcomes were the prevalence of cervical and VVP high-risk (HR) HPV. RESULTS: The prevalence of VVP HR-HPV was 39%, which was significantly higher than the cervical HR-HPV prevalence (26%, p<0.0001). HPV-16 was the most common genotype detected in both sites (VVP 11%, cervical 6%). HPV-16 infection peaked in women aged <20 years; however, there was a marked decline in cervical HPV-16 prevalence with age (p=0.007), whereas following an initial decline, the prevalence of VVP HPV-16 remained constant in subsequent age-groups (p=0.835). CONCLUSIONS: In this population experiencing a cluster of vulvar cancer, the prevalence of cervical oncogenic HPV infection was similar to that reported by studies of other Australian women; however there was a significantly higher prevalence of vulvar/vaginal/perianal infection to cervical. The large discrepancy in HPV prevalence between anogenital sites in this population may represent more persistent infection at the vulva. This needs further investigation, including the presence of possible environmental and/or genetic factors that may impair host immunity.

Comparison of the INNO-LiPA and PapType assays for detection of human papillomavirus in archival vulva dysplasia and/or neoplasia tissue biopsy specimens.

INNO-LiPA and PapType human papillomavirus (HPV) genotyping assays were compared for detection of HPV genotypes on archival vulvar tissue. The INNO-LiPA assay detected 49 HPV-16 infections, compared with 47 detected by the PapType assay. The INNO-LiPA assay detected amplifiable DNA in 59 (91%) biopsy specimens, compared with 57 (88%) specimens for which amplifiable DNA was detected by the PapType assay. The two genotyping assays were highly comparable.

Human papillomavirus genotyping using archival vulval dysplastic or neoplastic biopsy tissues: comparison between the INNO-LiPA and linear array assays.

The Roche Linear Array (LA) and Innogenetics INNO-LiPA human papillomavirus (HPV) genotyping assays were compared for paraffin-embedded vulval tissues. The LA detected amplifiable DNA in 28 (57%) out of 49 biopsy specimens, 20 (40%) being HPV genotyped, compared to 49 (100%) and 41 (83%), respectively, detected by the INNO-LiPA. The INNO-LiPA provides greater sensitivity for HPV genotyping in archival tissue.