p16 immunostaining in histological grading of anal squamous intraepithelial lesions: a systematic review and meta-analysis

Methylation markers for anal cancer screening: A repeated cross-sectional analysis of people living with HIV, 2015-2016

People living with HIV (PLWH) are at highest risk of anal cancer and will benefit from optimized screening for early disease detection. We compared host DNA methylation markers in high-grade squamous intraepithelial lesions (HSIL) versus samples negative for intraepithelial lesions (NILM) or low-grade intraepithelial lesions (LSIL) in PLWH. We recruited PLWH identifying as male aged ≥18 years undergoing high-resolution anoscopy (HRA) in Seattle, Washington, 2015-2016. Anal brush samples were collected for HPV detection, genotyping, and pyrosequencing methylation (host genes ASCL1, PAX1, FMN2, and ATP10A); clinical data were abstracted from medical records. We assessed associations between methylation and presence and extent of HSIL using generalized estimating equation logistic regression, adjusting for age, CD4 count and HIV viral load. Marker panels using HPV DNA and methylation were also evaluated to predict prevalent HSIL. We analyzed 125 samples from 85 participants (mean age 50.1; standard deviation 11.0 years). ASCL1 (adjusted odds ratio [aOR] per 1 unit increase mean percent methylation: 1.07, 95% CI: 1.01-1.13) and FMN2 (aOR per 1 unit increase mean percent methylation: 1.14, 95% CI: 1.08-1.20) methylation were significantly associated with HSIL versus NILM/LSIL. ASCL1 (aOR: 1.06, 95% CI: 1.01-1.11) and FMN2 (aOR: 1.13, 95% CI: 1.08-1.17) methylation were positively associated with increasing HSIL extent. A panel combining methylation (ASCL1 and FMN2) and HPV DNA (HPV16, HPV18, and HPV31) demonstrated best balance of sensitivity (78.2%) and specificity (73.9%) for HSIL detection compared with methylation or HPV alone. Increasing levels of DNA methylation of ASCL1 and FMN2 were positively associated with HSIL detection in PLWH. Host gene methylation testing shows promise for HSIL screening and triage.

Anal and Perianal Preneoplastic Lesions

Anal cancer, mainly squamous cell carcinoma, is rare but increasing in prevalence, as is its precursor lesion, anal squamous dysplasia. They are both strongly associated with human papillomavirus infection. The 2-tiered Lower Anogenital Squamous Terminology classification, low-grade SIL and high-grade SIL, is preferred to the 3-tiered anal intraepithelial neoplasia classification because of better interobserver agreement and clearer management implications. Immunohistochemistry with p16 is helpful to corroborate the diagnosis of squamous dysplasia. Similarly, immunohistochemistry is helpful to differentiate primary Paget disease from secondary Paget disease, which is usually due to anal squamous mucosal/epidermal involvement by primary rectal adenocarcinoma.

Comparison of clinicopathological and genomic profiles in anal squamous cell carcinoma between Japanese and Caucasian cohorts

Anal squamous cell carcinoma (ASCC) is a rare tumor of the gastrointestinal tract. We aimed to compare the genetic backgrounds and their effect on clinical outcomes between Japanese and Caucasian patients with ASCC. Forty-one patients diagnosed with ASCC at the National Cancer Center Hospital were enrolled and evaluated for clinicopathological features, human papillomavirus (HPV) infection, HPV genotypes, p16 expression, PD-L1, and association of p16 status with the efficacy of concurrent chemoradiotherapy (CCRT). Target sequencing for hotspot mutations in 50 cancer-related genes was performed using genomic DNA from 30 available samples. Of 41 patients, 34 were HPV-positive (among them, HPV 16 was predominant; 73.2%); 38 patients were p16-positive (92.7%); and 39 patients received CCRT, of whom 36 were p16-positive and three p16-negative. p16-positive patients showed better complete response than p16-negative patients. Among 28 samples, 15 showed mutations in PIK3CA, FBXW7, ABL1, TP53, and PTEN; no difference in mutation profiles between the Japanese and Caucasian cohorts was observed. Actionable mutations were detected in both Japanese and Caucasian patients with ASCC. Genetic backgrounds, such as the HPV 16 genotype and PIK3CA mutations, were common regardless of ethnicity. p16 status may be a prognostic biomarker for CCRT in Japanese patients with ASCC.

Anal intraepithelial neoplasia: a review of terminology, differential diagnoses, and patient management

Despite the knowledge of etiological association with high-risk human papilloma viruses and high-risk patient cohorts, the incidence of anal squamous cell carcinoma has continued to rise. The known precursor lesion (in particular, high-grade squamous intraepithelial lesion) makes it amenable to screening and surveillance strategies. However, the diagnosis of anal intraepithelial neoplasia suffers from interpretation challenges leading to high interobserver variability, along with numerous differential diagnoses and lingering terminology issues. Proper treatment of anal lesions requires accurate diagnosis, and while a variety of modalities are available for treatment, the rate of recurrence remains high and each modality has its own set of side effects and complications. The aim of this review article is to outline the diagnostic considerations and provide practical tips for diagnosing anal squamous intraepithelial lesions.

p16 Immunoreactivity Correlates With Morphologic Diagnosis of HPV-associated Anal Intraepithelial Neoplasia: A Study of 1000 Biopsies

p16 is the most useful diagnostic marker for human papillomavirus (HPV)-associated anogenital lesions. In the cervix, the pattern of p16 immunoreactivity generally correlates with lesion severity. p16 expression in anal intraepithelial neoplasia (AIN) is far less studied. Whether such correlation holds true has to be determined. We correlated the degree and pattern of p16 immunohistochemistry (IHC) results with morphologic diagnoses of 1000 anal squamous and transitional zone biopsy specimens. Using the Lower Anogenital Squamous Terminology criteria, p16 IHC results were classified as block staining, partial staining, or negative. Among 150 samples without morphologic evidence of AIN, p16 was negative in 85% and partial staining in 15%. AIN 1 (n=400) revealed diverse results: 28% negative, 35% partial, and 37% block staining. Among AIN 2 (n=298), 89% were block, 9% partial staining, and 2% negative. AIN 3 (n=152) revealed block (95%) or partial staining (5%). For the detection of AIN 2/3, p16 block staining yielded 91% sensitivity, 73% specificity, 80% positive predictive value, 91% negative predictive value, and a Youden Index of 0.64. Combining block staining and partial staining slightly increased sensitivity (99%) and negative predictive value (98%), but significantly decreased specificity (43%), positive predictive value (59%) and Youden Index (0.42, P<0.001). As with the cervix, p16 immunoreactivity correlates with morphologic diagnoses of AIN. Block staining offers the optimal diagnostic value for AIN 2/3. Caution is required since AIN 1 frequently exhibits block staining; the prognostic value of p16 warrants further investigation.

HPV-driven anal neoplasia: review and recent developments

A host of human papillomavirus (HPV)-associated squamous and glandular lesions may be identified in the anal canal in men and women. Given their relative rarity, familiarity with the morphological spectrum associated with HPV-driven anal neoplasia is important for proper identification and diagnosis. In this article, we review the classification and basic histopathological features of HPV-related squamous intraepithelial and invasive lesions as well as associated pitfalls. In addition, we provide an update on recently described HPV-driven, non-squamous tumours. As our experience with these lesions evolves, we expect the histological spectrum to further expand, particularly as it relates to non-squamous HPV-driven neoplasia.

Characterisation of anal intraepithelial neoplasia and anal cancer in HIV-positive men by immunohistochemical markers p16, Ki-67, HPV-E4 and DNA methylation markers

Human papillomavirus (HPV)-induced anal intraepithelial neoplasia (AIN, graded 1-3) is highly prevalent in HIV-positive (HIV+) men who have sex with men (MSM), but only a minority of lesions progresses to cancer. Our study aimed to characterise comprehensively anal tissue samples from a cross-sectional series (n = 104) of HIV+ MSM and longitudinal series (n = 40) of AIN2/3 progressing to cancer using different biomarkers. The cross-sectional series consisted of 8 normal, 26 AIN1, 45 AIN2, 15 AIN3 and 10 anal squamous cell carcinoma. Tissue sections were immunohistochemically (IHC) stained for p16 (viral transformation marker), Ki-67 (cellular proliferation marker) and HPV-E4 (viral production marker). We evaluated the expression of IHC markers and compared it with DNA methylation, a marker for malignant transformation. E4 positivity decreased, whereas p16 and Ki-67 scores and methylation marker positivity increased (P values < .001) with increasing severity of anal lesions. Within AIN2, a heterogeneous biomarker pattern was observed concerning E4, p16 and methylation status, reflecting the biological heterogeneity of these lesions. In the longitudinal series, all AIN2/3 and carcinomas showed high p16 and Ki-67 expression, strong methylation positivity and occasional E4 positivity. We earlier showed that high methylation levels are associated with progression to cancer. The observed E4 expression in some AIN2/3 during the course of progression to cancer and absence of E4 in a considerable number of AIN1 lesions make the potential clinical significance of E4 expression difficult to interpret. Our data show that IHC biomarkers can help to characterise AIN; however, their prognostic value for cancer risk stratification, next to objective methylation analysis, appears to be limited.

Different patterns of p16INK4a immunohistochemical expression and their biological implications in laryngeal squamous cell carcinoma

Introduction: p16^INK4a immunohistochemistry (IHC) is widely used to facilitate the diagnosis of human papillomavirus (HPV)-associated neoplasia, when ≥70% of cells show strong nuclear and cytoplasmic positivity. In this study, we aim to compare partial expression patterns that do not fulfill the above criteria and seek biological implications in laryngeal squamous cell carcinoma (LSCC). Materials and Methods: p16^INK4a IHC staining was conducted on representative sections of archived tissue from 88 LSCCs. Immunoreactivity was described based on four parameters: intracellular localization of immunostaining, intensity of immunostaining, distribution pattern and percentage of positive cells. Results: Six patterns of p16^INK4a immunoexpression were observed and defined as: strong diffuse (strong immunostaining, expression in cytoplasm and nucleus in >70% of tumor cells), weak diffuse (moderate or weak immunostaining, expression in cytoplasm in >70% of tumor cells), marginal (strong cytoplasmic immunostaining, limited to the periphery of tumor islets), strong scattered (strong immunostaining, expression in cytoplasm and nucleus in <50% of tumor cells), weak scattered (moderate or weak immunostaining, expression in cytoplasm in <50% of tumor cells), negative (no expression). The pN stage of the patients was associated with p16^INK4a immunoexpression patterns, the marginal pattern was only found in the pN0-Nx stages, while the weak diffuse pattern was more frequently observed in pN2-N3 stages. Conclusions: Partial immunostaining with architecturally distinct p16^INK4a immunoexpression patterns may prove significant in stratifying characteristic clinicopathological subgroups among LSCC. Our observations may support the hypothesis that p16^INK4a has different roles in different subcellular locations, with tumorigenic molecular pathways unrelated to HPV infection.

Juvenile-Onset Recurrent Respiratory Papillomatosis Aggressiveness: In Situ Study of the Level of Transcription of HPV E6 and E7

Simple Summary

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is a condition related to HPV 6 and 11 infection which is characterized by the repeated growth of benign exophytic papilloma in the respiratory tract of children. Disease progression is unpredictable leading sometimes to airway compromise and death. The aim of this study was to explore p16^INK4a and expression of the RNA of HPV genes E6 and E7 with a chromogenic in situ hybridization (CISH) as biomarkers of JoRRP aggressiveness on a bicentric cohort of forty-eight children. CISH was scored semi-quantitatively as high (2+ score) and low (1+ score) levels of transcription of E6 and E7. Patients with a 2+ score had a more aggressive disease compared to those with a 1+ score. These data are a first step towards the use of biomarkers predictive of disease severity in JoRRP, this could improve the disease management, for example, by implementing adjuvant treatment at the early stages.

Abstract

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is a condition related to HPV 6 and 11 infection which is characterized by the repeated growth of benign exophytic papilloma in the respiratory tract. Disease progression is unpredictable: some children experience minor symptoms, while others require multiple interventions due to florid growth. The aim of this study was to explore the biomarkers of JoRRP severity on a bicentric cohort of forty-eight children. We performed a CISH on the most recent sample of papilloma with a probe targeting the mRNA of the E6 and E7 genes of HPV 6 and 11 and an immunostaining with p16^INK4a antibody. For each patient HPV RNA CISH staining was assessed semi-quantitatively to define two scores: 1+, defined as a low staining extent, and 2+, defined as a high staining extent. This series contained 19 patients with a score of 1+ and 29 with a score of 2+. Patients with a score of 2+ had a median of surgical excision (SE) per year that was twice that of patients with a score of 1+ (respectively 6.1 versus 2.8, p = 0.036). We found similar results with the median number of SE the first year. Regarding p16^INK4a, all patients were negative. To conclude, HPV RNA CISH might be a biomarker which is predictive of disease aggressiveness in JoRRP, and might help in patient care management.

Diagnosing Anal Squamous Intraepithelial Lesions With and Without p16: An Interobserver Variability Study

OBJECTIVE

Morphologic diagnosis and grading of anal squamous intraepithelial lesions (ASILs) are challenging. In this study, we investigated interobserver variability and p16 utility in accurately grading anal SIL.

MATERIALS AND METHODS

Six pathologists evaluated the degree of SIL on hematoxylin and eosin slides from 146 anal biopsies, followed by the review of both p16 and hematoxylin and eosin slides in cases where p16 was previously performed. κ was calculated in the following 4 ways: (A) 4-tiered diagnosis (negative for SIL [NSIL], anal intraepithelial neoplasia [AIN 1, AIN 2, AIN 3]); (B) 3-tiered diagnosis (NSIL and AIN 1 [pooled], AIN 2, AIN 3); (A) 3-tiered diagnosis (NSIL, low-grade SIL, high-grade SIL [HSIL]); and (D) 2-tiered diagnosis (no HSIL, HSIL).

RESULTS

There is only moderate agreement with a 4-tiered diagnosis with or without p16 (κ = 0.48-0.57). There is substantial agreement when AIN 2 and AIN 3 are pooled as HSIL in cases with or without p16 review (κ = 0.71-0.78). There is almost perfect agreement with a 2-tiered diagnosis of negative for HSIL and HSIL both in cases where p16 was used and where p16 was not required, with the best agreement for a 2-tiered diagnosis with concurrent p16 review.

CONCLUSIONS

This study highlights the importance of a judicious use of p16 for diagnosis. When there is no need for p16 by the Lower Anogenital Squamous Terminology guidelines, interobserver agreement was substantial to almost perfect with a 2-tiered diagnosis. However, when its use is indicated but it is not performed or reviewed, the agreement is much lower even with a 2-tiered diagnosis. Rational use of p16 will ensure diagnostic accuracy and the best possible patient care.

An Update on the Role of Immunohistochemistry in the Evaluation of Gastrointestinal Tract Disorders

As in other organ systems, immunohistochemistry (IHC) serves as an ancillary diagnostic tool for a wide variety of neoplastic and non-neoplastic disorders, including infections, work-up of inflammatory conditions, and subtyping neoplasms of the gastrointestinal (GI) tract. In addition, IHC is also used to detect a variety of prognostic and predictive molecular biomarkers for carcinomas of the GI tract. The purpose of this review is to highlight the use of IHC in common diagnostic scenarios throughout the tubular GI tract. The clinical indication and guidelines for performing IHC for detecting Helicobacter pylori is discussed along with role of gastrin and neuroendocrine markers in the diagnosis of autoimmune metaplastic atrophic gastritis. The major portion of this review discusses the use of IHC in the diagnostic workup of malignant neoplasms of the GI tract, such as adenocarcinoma versus squamous cell carcinoma, workup of poorly differentiated malignant neoplasms, and evaluation of uncommon gastric neoplasms (alpha-feto protein-producing carcinomas) and switch/sucrose-nonfermenting complex-deficient carcinomas. Lastly, localization of neuroendocrine tumors of unknown origin to aid clinical management, as well as HPV-driven anal neoplasia and IHC in the workup of basaloid anal neoplasms are also reviewed.

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.