P16 and Ki67 Immunostains Decrease Intra- and Interobserver Variability in the Diagnosis and Grading of Anal Intraepithelial Neoplasia (AIN)

Classifying Anal Intraepithelial Neoplasia 2 Based on LAST Recommendations

OBJECTIVES

The Lower Anogenital Squamous Terminology (LAST) recommendations classify human papillomavirus-associated squamous lesions into low- and high-grade squamous intraepithelial lesions (LSILs/HSILs). Our study aimed to assess interobserver agreement among 6 experienced pathologists in assigning 40 anal lesions previously diagnosed as anal intraepithelial neoplasia 2 (AIN 2) to either HSIL or non-HSIL categories.

METHODS

Agreement based on photomicrographs of H&E alone or H&E plus p16 immunohistochemistry was calculated using κ coefficients.

RESULTS

Agreement was fair based on H&E alone (κ = 0.42; 95% confidence interval [CI], 0.34-0.52). Adding p16 improved agreement to moderate (κ = 0.55; 95% CI, 0.54-0.62). On final diagnosis, 21 cases (53%) had unanimous diagnoses, and 19 (47%) were divided. When designating p16 results as positive or negative, agreement was excellent (κ = 0.92; 95% CI, 0.83-0.95). Among variables (staining location, extent, and intensity), staining of the basal/parabasal layers was a consistent feature in cases with consensus for positive results (20/20). Of the 67 H&E diagnoses with conflicting p16 results, participants modified 32 (48%), downgrading 23 HSILs and upgrading 9 non-HSILs.

CONCLUSIONS

Although p16 increased interobserver agreement, disagreement remained considerable regarding intermediate lesions. p16 expression, particularly if negative, can reduce unwarranted HSIL diagnoses and unnecessary treatment.

Anal prevalence of HPV in women with pre-malignant lesion or cancer in the cervix and anal canal simultaneously: cross-sectional study

OBJECTIVE

To determine the prevalence of anal HPV genotypes and associated factors in women with pre-malignant lesion or cancer in the cervix and anal canal.

METHODS

A prospective, cross-sectional study analyzed DNA samples taken from women with cervical pre-malignant lesions or cancer to identify anal HPV by polymerase chain reaction (PCR). The prevalence of high-risk HPV (HR-HPV) in women with intraepithelial neoplasia and anal cancer was calculated; sociodemographic and clinical risk factors were identified using multivariate analysis.

RESULTS

A total of 152 patients were included (mean age 37.8 ± 10.01 years), of whom 101 (66.4%) had anal HR-HPV. Fourteen different anal HPV types were identified. HPV 16 and 18 were found in 30 (52.6%) anal high-grade squamous intraepithelial lesions (HSIL), and HPV 31 and 33 in 21 (36.8%) lesions. In the logistic regression analysis, the factors that remained associated with HR-HPV types were: an anal histopathology report of HSIL or invasive carcinoma (odds ratio [OR] 8.96, 95% confidence interval [CI] 3.40-23.57; P<0.0001) and alcohol consumption (OR 2.20, 95% CI 1.01-4.80; P=0.04).

CONCLUSION

Prevalence of HR-HPV is high in the anal canal of women with cervical and anal pre-malignant lesions simultaneously or cancer of the cervix and/or anal canal. HPV 16, 31, 33, and 18 were the four major genotypes identified.

New Insights into the Role of Human Papillomavirus in Anal Cancer and Anal Wart Development

Human papillomavirus is associated with several anogenital and oropharyngeal lesions, including warts, premalignant lesions, and cancer. There are specific groups that were identified as high-risk groups for anal squamous cell carcinoma and anal human papillomavirus infection, namely HIV-positive patients, men who have sex with men, women with genital tract neoplasia, and solid organ transplant recipients. Condylomas have classically been considered to be a benign lesion, with an exception made for the Buschke-Loewenstein tumor, but several publications have shown that a high percentage of condylomas harbor high-grade lesions. Due to the similarities between anal and cervical carcinogenesis, anal cancer screening based on anal cytology and referral to high-resolution anoscopy, in case of abnormalities, have been advocated. Testing for anal human papillomavirus is not routinely done in anal cancer screening, because of the very high prevalence in high-risk populations. The large majority of anal cancers are squamous cell carcinomas (SCC), and around 90% are attributed to human papillomavirus. Human papillomavirus positivity in anal SCC seems to have a prognostic value, with better survival in those patients with positive tumors. Prophylactic vaccination has been shown to be important for prevention of anal human papillomavirus-related lesions.

Expression of microRNAs 16, 20a, 150 and 155 in anal squamous intraepithelial lesions from high-risk groups

Anal squamous intraepithelial lesions (ASIL) or anal intraepithelial neoplasia (AIN) are precancerous lesions. microRNAs (miRNAs) have been implicated in cervical carcinogenesis, but have never been assessed in anal precancerous lesions. Our aim was to evaluate the expression of miR-16, miR-20a, miR-150 and miR-155 in several grades of ASIL obtained from high-risk patients, submitted to anal cancer screening from July 2016 to January 2017. Lesions were classified according to the Lower Anogenital Squamous Terminology (LAST) in low-grade (LSIL) and high-grade squamous intraepithelial lesions (HSIL), and the AIN classification in AIN1, AIN2 and AIN3. A hundred and five biopsies were obtained from 60 patients. Ten samples were negative (9.5%), 63 were LSIL (60%) and 32 were HSIL (30.5%) according to the LAST. Twenty seven (26%) were negative for dysplasia, 46 were classified as AIN1 (44%), 14 as AIN2 (13%) and 18 as AIN3 (17%) according to the AIN classification. There was no statistically significant difference in the fold expression of miR-16, miR-20a, miR-150 and miR-155, according to either classification. Although non- significant, there was an increasing trend in the miR-155 fold expression from negative samples to HSIL, with the highest fold expression increase in both LSIL and HSIL compared to the other miRNAs.

Characterization of topoisomerase II α and minichromosome maintenance protein 2 expression in anal carcinoma

The present study aimed to ascertain the significance of topoisomerase II α (TOP2A) and minichromosome maintenance protein (MCM) 2 expression in anal carcinoma. A total of 75 anal lesions were retrieved from the files of the Department of Pathology of Barretos Cancer Hospital (Barretos, Brazil) in order to verify the human papillomavirus (HPV) statuses of these lesions and characterize the immunohistochemical expression levels of TOP2A and MCM2 in anal carcinoma, as these are important markers for cervical HPV-induced lesions; their expression was also compared with respect to p16 and Ki-67. The vast majority of the cases tested positive for HPV16 (84%); 1 case tested positive for both HPV16 and HPV18. Positive HPV16 status was more frequent in early stages than in advanced stages (P=0.008). Positive immunohistochemical reactivity for MCM2 and TOP2A protein was observed in 71.6 and 100% of cases, respectively. Positive reactivity for p16 was significantly associated (P=0.001) with histological grade, and was more commonly expressed in squamous cell carcinoma than adenocarcinomas. HPV16 was strongly associated with positive p16 protein expression (76.6%). However, the high expression of Ki-67 combined with the high expression of p16 was predominantly observed in Stage III-IV cases. MCM2, TOP2A, p16 and Ki-67 exhibited intense positive staining in the anal lesions, indicating that these markers were significantly and constantly expressed in anal carcinoma.

Grading of atypia in genital skin lesions: routine microscopic evaluation and use of p16 immunostaining

BACKGROUND

p16 immunostaining has been used to aid and improve the histopathologic evaluation of equivocal cervical lesions with associated low-grade or high-grade dysplasia. However, the utility of p16 immunostaining in the diagnosis of atypical genital skin lesions remains debatable.

METHODS

We conducted a cross-sectional study of genital skin lesions with varying degrees of atypia. Four pathologists assessed lesional atypia and interpreted hematoxylin and eosin (H&E) staining and p16 immunostaining without knowledge of original diagnosis. Our primary outcomes were diagnostic agreement and test performance of p16 immunostaining compared to consensus H&E diagnosis.

RESULTS

Our sample was comprised of 23 cases of atypical genital skin lesions. p16 immunostaining was negative in all cases of reactive atypia (n = 3) and the majority (n = 7 of 8; 88%) of low-grade squamous intraepithelial lesions (LSILs). The majority (n = 10 of 12; 83%) of high-grade squamous intraepithelial lesions (HSIL) were p16 positive. Diagnostic agreement for histopathologic assessment using H&E staining was moderate (kappa = 0.44), while inter-observer agreement of p16 immunostaining was excellent (kappa = 0.87). Compared to consensus diagnosis using H&E staining, p16 immunostaining performed well (sensitivity 83.3%; specificity 90.9%).

CONCLUSIONS

p16 immunostaining may be a useful adjunctive marker for assessing dysplasia in genital skin lesions and increasing diagnostic agreement among pathologists.

Anal intraepithelial neoplasia: a single centre 19 year review

AIM

There is debate about whether the traditional three-tiered grading of anal intraepithelial neoplasia (AIN) should be replaced by a more reproducible two-tiered system. In this study, we review our experience with AIN to determine the most suitable classification system.

METHOD

We performed a retrospective review of all histological reports over a 19 year period. All specimens were graded on haemataloxin and eosin appearance and those with dysplasia had immunohistochemistry for p16 and Ki67 performed.

RESULTS

Cases included 25 condyloma acuminata, 11 dysplastic cases and 24 invasive squamous cell carcinomas. On review, 18 were classified as condyloma acuminata without dysplasia. Seven had AIN I, five had AIN II and six had AIN III when using a three-tiered system. All cases classified as dysplastic (n = 18) showed an increased proliferation index as measured by Ki67. p16 positivity was seen in all AIN III, two AIN II and none of the AIN I cases. Recurrence was not observed in any of the AIN I cases. Five of eleven AIN II and AIN III cases recurred or persisted at a similar, higher or lower grade. Both of the AIN II cases which recurred or persisted were p16 positive. None of the AIN II cases that were p16 negative recurred. Three of the p16-positive AIN III cases did not recur. None of the 18 AIN cases progressed to carcinoma.

CONCLUSION

The findings support the slow progression of AIN as described in the literature. In our small series, a two-tiered system with further subclassification of the traditional AIN II group using p16 appears to be clinically useful.

P16 and Ki67 Immunostains Decrease Intra- and Interobserver Variability in the Diagnosis and Grading of Anal Intraepithelial Neoplasia (AIN)

BACKGROUND

Significant variation is reported in the diagnosis of HPV-associated AIN. We previously observed that band-like positivity for p16 in >90% of contiguous cells coupled with Ki67 positivity in >50% of lesional cells is strongly associated with high grade AIN. This study was undertaken to determine if addition of p16 and Ki67 immunostaining would reduce inter- and intraobserver variability in diagnosis and grading of AIN.

DESIGN

H&E stained slides of 60 anal biopsies were reviewed by three pathologists and consensus diagnoses were achieved: 25 negative, 12 low (condyloma and/or AIN I) and 23 high (9 AIN II and 14 AIN III) grade lesions. The H&E stained slides were diagnosed independently by three additional ("participant") pathologists. Several weeks later they re-examined these slides in conjunction with corresponding p16 and Ki67 immunostains.

RESULTS

Addition of p16 and Ki67 immunostains reduced intra- and interobserver variability, improved concurrence with consensus diagnoses and reduced two-step differences in diagnosis. Negative and high grade AIN diagnoses showed the most improvement in concurrence levels.

CONCLUSION

Addition of p16 and Ki67 immunostains is helpful in the diagnosis and grading of AIN.