Laser Microdissection for Human Papillomavirus (HPV) Genotyping Attribution and Methylation Pattern Analyses of Squamous Intraepithelial Lesions

DNA methylation at individual CpG-sites of EPB41L3, HTERT and FAM19A4 are useful for detection of cervical high-grade squamous intraepithelial lesions (HSIL) or worse: Analysis of individual CpG-sites outperforms averaging

Global methylation analysis of gene promoters is promising for detection of high-grade squamous intraepithelial lesions or worse (HSIL+) in high-risk human papillomavirus (hrHPV)-positive women. However, diagnostic performance of methylation data at individual CpG-sites is limited. We explored methylation for predicting HSIL+ in self- and clinician-collected samples from Papua New Guinea. Methylation of EPB41L3 (1-6 CpG-sites), hTERT (1-10 CpG-sites) and FAM19A4 (1-5 CpG-sites) was assessed through pyrosequencing from 44 HPV+ samples (4 cancers, 19 HSIL, 4 low-grade squamous intraepithelial lesions (LSIL), 17 normal). New primers were designed for FAM19A4 directed to the first exon region not explored previously. In clinician-collected samples, methylation at CpG-sites 4 and 5 of EPB41L3 were the best HSIL predictors (AUC >0.83) and CpG-site 4 for cancer (0.925). Combination of EPB41L3 sites 2/4 plus FAM19A4 site 1 were the best HSIL+ markers [100% sensitivity, 63.2% specificity]. Methylation at CpG-site 5 of FAM19A4 was the best HSIL predictor (0.67) in self-collected samples, and CpG-sites 1 and 3 of FAM19A4 for cancer (0.77). Combined, FAM19A4 site 1 plus HPV 16/18 detection yielded sensitivity of 82.6% and specificity of 61.9%. In conclusion, methylation at individual CpG-sites of EPB41L3 and FAM19A4 outperformed global analysis and improved HSIL+ detection, warranting further investigation.

Comparison of four assays for human papillomavirus detection in the anal canal

OBJECTIVES

Anal cancer is preceded by high-risk human papillomavirus (HRHPV) infection, predominantly HPV16. No HPV assay is licenced for use in anal screening. We aimed to determine the sensitivity and specificity of four anal canal swab HPV assays to predict high grade squamous epithelial lesions (HSIL).

METHODS

In a cohort of Australian HIV-positive and negative gay and bisexual men, we compared the sensitivity and specificity of detection of 13 anal HRHPV genotypes by Linear Array (LA), Cobas 4800, EuroArray and Anyplex II HPV28 (+ and ++ cut offs), compared their ability to predict prevalent anal HSIL and compared anal canal HRHPV detection with HRHPV isolated from HSIL using laser capture microdissection (LCM).

RESULTS

A total of 475 participants had baseline results available for all 4 assays (166, 35.0% HIV positive), and 169 participants had a diagnosis of cytological and/or histological HSIL.HPV16 and any HRHPV detection were highest with Anyplex II HPV28 (+) (156, 32.8% 95% CI 28.6-37.2 and 359, 75.6%, 95% CI 71.5-79.4 respectively). For detection of concurrent HSIL and HPV16, the assay sensitivity was similar ranging from 49.1%, 95% CI 41.4-56.9 (Anyplex II HPV28 ++) to 55.0%, 95% CI 47.2-62.7 (Anyplex II HPV28 +). For concurrent HSIL and any HRHPV detection, EuroArray was more specific than Anyplex II HPV28 (+) (45.9% 95% CI 40.2-51.7 vs 36.7%, 95% CI 31.3-42.4, p=0.021) and had comparable specificity with Anyplex II HPV28 (++) (45.9% vs 47.2%, 95% CI 41.5-53.0, p=0.75). All assays had high sensitivities for predicting HPV16 detected on LCM (92.5-97.5%). Anyplex II HPV28 and EuroArray were significantly more sensitive than LA for lesions caused by non-HPV16 HRHPV types on LCM.

CONCLUSION

Anyplex II HPV28 and EuroArray detected more non-16 HRHPV genotypes than LA. Increasing the Anyplex II HPV28 cut off improved specificity, without compromising sensitivity for detection of concurrent HSIL.

Human Papillomavirus Genotypes in Anal High-Grade Squamous Intraepithelial Lesion (HSIL): Anal Intraepithelial Neoplasia Grades 2 (AIN2) and 3 (AIN3) Are Different

BACKGROUND

Anal high-grade squamous intraepithelial lesion (HSIL) can be histomorphologically categorized into anal intraepithelial neoplasia (AIN) grade 2 (AIN2) and grade 3 (AIN3). Different risk factors for these two categories have been described. We investigated whether there were also differences in lesion-specific human papillomavirus (HPV) genotypes.

METHODS

The Study of the Prevention of Anal Cancer (SPANC) recruited 617 gay and bisexual men (GBM); 36% of participants were HIV positive. At baseline, 196 men (31.8%) had histologic HSIL lesions. Tissue was available for genotyping in 171, with a total of 239 HSIL lesions (183 AIN3 and 56 AIN2). Using laser capture microdissection, each lesion revealed a maximum of one genotype.

RESULTS

High-risk HPV (HR-HPV) genotypes were found in 220 (92.1%) HSIL lesions, with no significant difference between AIN3 (93.4%) and AIN2 (87.5%). AIN3 lesions had significantly more HPV16 (42.1%) than AIN2 lesions (12.5%; P < 0.001) and AIN2 lesions had significantly more non-16 HR-HPV types (75.0%) than AIN3 lesions (51.4%; P = 0.002). These associations were similar for HIV-negative men with HPV16 in 51.1% AIN3 and 18.2% AIN2 (P = 0.001) and non-16 HR-HPV in 40.0% AIN3 and 75.8% AIN2 (P < 0.001). For HIV-positive men, HPV16 remained more frequently detected in AIN3 (33.3% vs. 4.4% for AIN2; P = 0.004), but there was no difference between AIN3 and AIN2 for non-16 HR-HPV (62.4% vs. 73.9%; P = 0.300).

CONCLUSIONS

As HPV16 has the strongest link with anal cancer, the subcategorization of HSIL may enable stratification of lesions for anal cancer risk and guide anal HSIL management.

IMPACT

Stratification of anal cancer risk by histologic HSIL grade.