Immunohistochemical Expression of p16 and Ki-67 Correlates With Degree of Anal Intraepithelial Neoplasia

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.

Screening for precancerous anal lesions linked to human papillomaviruses: French recommendations for clinical practice

In France, about 2000 new cases of anal cancer are diagnosed annually. Squamous cell carcinoma is the most common histological type, mostly occurring secondary to persistent HPV16 infection. Invasive cancer is preceded by precancerous lesions. In addition to patients with a personal history of precancerous lesions and anal cancer, three groups are at very high risk of anal cancer: (i) men who have sex with men and are living with HIV, (ii) women with a history of high-grade squamous intraepithelial lesions (HSILs) or vulvar HPV cancer, and (iii) women who received a solid organ transplant more than 10 years ago. The purpose of screening is to detect HSILs so that they can be treated, thereby reducing the risk of progression to cancer. All patients with symptoms should undergo a proctological examination including standard anoscopy. For asymptomatic patients at risk, an initial HPV16 test makes it possible to target patients at risk of HSILs likely to progress to cancer. Anal cytology is a sensitive test for HSIL detection. Its sensitivity is greater than 80% and exceeds that of proctological examination with standard anoscopy. It is indicated in the event of a positive HPV16 test. In the presence of cytological abnormalities and/or lesions and a suspicion of dysplasia on clinical examination, high-resolution anoscopy is indicated. Performance is superior to that of proctological examination with standard anoscopy. However, this technique is not widely available, which limits its use. If high-resolution anoscopy is not possible, screening by a standard proctological examination is an alternative. There is a need to develop high-resolution anoscopy and triage tests and to evaluate screening strategies.

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.

Interobserver Agreement in the Diagnosis of Anal Dysplasia: Comparison Between Gastrointestinal and Gynaecologic Pathologists and Utility of Consensus Conferences

INTRODUCTION

Management of anal dysplasia relies on the accurate diagnosis of anal biopsy specimens. As institutions move toward subspecialty signout (SSSO), decisions must be made regarding whether to assign anal biopsies to the gastrointestinal (GI) or gynaecologic (GYN) pathology service.

MATERIALS AND METHODS

We identified 200 archival tissue biopsies of anal mucosa and circulated them among three GI pathologists and three GYN pathologists. Each pathologist separately scored each biopsy as normal, atypical, LSIL, or HSIL. Every case that was called HSIL by at least one pathologist was stained with p16 immunostain and a "gold standard" interpretation of whether a case represented HSIL was made.

RESULTS

The GI pathologists agreed on 97 (49%) cases prior to consensus; the GYN pathologists agreed on 33 (17%). The sensitivities of the 3 GI pathologists in detecting HSIL against the "gold standard" were 47%, 100%, and 21%, and for the GYN pathologists the sensitivities were 74%, 89%, and 84%; the sensitivities of both the GI and GYN consensus diagnoses were 74% each. The specificities of the 3 GI pathologists in detecting HSIL were 99%, 90%, and 100%, and for the GYN pathologists the specificities were 99%, 92%, and 91%; the specificities of both the GI and GYN consensus diagnoses were 100%.

CONCLUSIONS

A mild to moderate degree of interobserver variability exists in the diagnosis of anal dysplasia among pathologists. Our study does indicate the utility of some form of consensus conference, as overall agreement among GI pathologists and among GYN pathologists improved following in-person consensus.

Comparing and contrasting clinical consensus and guidelines for anal intraepithelial neoplasia in different geographical regions

Anal Squamous Cell Carcinoma (ASCC) is an uncommon cancer with a recognised precursor Anal Intraepithelial Neoplasia (AIN). Although there are consistent evidence-based guidelines for the management of ASCC, historically this has not been the case for AIN and as a result there have been geographical variations in the recommendations for the treatment of AIN. More recently there have been updates in the literature to the recommendations for the management of AIN. To assess whether we are now closer to achieving an international consensus, we have completed a systematic scoping review of available guidelines for the screening, treatment and follow-up of AIN as a precursor to ASCC. MEDLINE and EMBASE were systematically searched for available clinical guidelines endorsed by a recognised clinical society that included recommendations on either the screening, treatment or follow-up of AIN. Nine clinical guidelines from three geographical areas were included. The most recent guidelines agreed that screening for AIN in high-risk patients and follow-up after treatment was necessary but there was less consensus on the modality of screening. Six Guidelines recommended the treatment of high-grade AIN and four guidelines describe a follow-up protocol of patients diagnosed with AIN. There appears to be increasing consensus on the treatment and follow-up of patients despite a poor evidence base. There is still significant discrepancy in guidance on the method to identify patients at risk of ASCC and AIN despite consensus between geographical regions on which patient subgroups are at the highest risk.

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.

Clinical efficacy and mechanism for focused ultrasound (FUS) in the management of cervical intraepithelial neoplasia 1 (CIN1)

Objective: This study was aimed at investigating the clinical efficacy and studying the possible mechanism of FUS applications to treat cervical intraepithelial neoplasia 1 (CIN1).Methods: This was a prospective clinical study, in which 30 patients with CIN1 (28/30 of the patients were HPV positive) were enrolled and treated with FUS therapy by gynecologist. All patients were followed up for 3 months after FUS therapy. Telephone interviews, PAP smear, colposcopic examinations, cervical biopsies and HPVDNA tests were performed to assess the safety and effectiveness of FUS therapy for HPV-positive CIN1. The expression of p16, Ki-67 and Fas in the cervical tissues were examined in order to account for the possible mechanism of FUS therapy for CIN1 with HPV infection.Results: FUS therapy was tolerated well, and no severe complications were observed in any patient. After FUS treatment, twenty-five patients were cured completely, and two cases were improved with the cervical smear results reversed to normal, and three cases remained the same status as before treatment. The total effectiveness rate was 90.00% (27/30). The expression of P16 and Ki-67 in the treated cervical tissues was significantly lower than that before treatment, and the expression of Fas was found up-regulated (all p < .05).Conclusion: FUS therapy appears to be a feasible and effective treatment for patients with HPV positive CIN1. FUS therapy may help to reduce the expression of p16 and Ki-67 and enhance the expression of Fas in the treated cervical tissues to regulate cell proliferation and increase apoptosis, and thus prevent the disease from evolving into high grade lesions.

Presence or Absence of Significant HPVE4 Expression in High-grade Anal Intraepithelial Neoplasia With p16/Ki-67 Positivity Indicates Distinct Patterns of Neoplasia: A Study Combining Immunohistochemistry and Laser Capture Microdissection PCR

Progression of anal intraepithelial neoplasia (AIN) involves transition from productive to transforming human papillomavirus (HPV) infection. Grading aims to distinguish productive low-grade AIN from high-grade anal intraepithelial neoplasia (HGAIN) with risk of cancer. We describe immunohistochemical patterns in AIN adding a novel marker for initiation of the productive phase of the HPV life cycle (panHPVE4) to those for cell cycle activity (Ki-67) and transforming activity of HPVE7 gene (p16). We studied 67 anal biopsies for suspected anal neoplasia (17 normal, 15 AIN1, 20 AIN2, 15 AIN3) from 54 men who have sex with men at New York Presbyterian Hospital, USA. Two pathologists generated consensus AIN and immunogrades. Whole tissue and laser capture microdissection samples from multiple HPV-infected biopsies were tested for HPV with SPF10-PCR-DEIA-LiPA25, version 1. (Para)basal Ki-67 expression distinguished normal from AIN (≥lower-third Ki-67) with sensitivity 0.92 and specificity 1.0. Ki-67 did not distinguish grades of AIN. Null/patchy p16 versus diffuse ≥lower-third patterns discriminated HGAIN (sensitivity, 1.0; specificity, 0.84). There was marked heterogeneity in E4 expression within HGAIN. Most AIN2 (14/20) was E4 versus 0/15 AIN3 (sensitivity, 0.70; specificity 1.0). HPV was detected in 63 (94%) biopsies, with 49 (77.8%) high-risk HPV. HPV16 was the most frequent (13%). Multiple HPV genotypes were found in 15 (24%) biopsies and laser capture microdissection -polymerase chain reaction confirmed specific HPV types in E4 +/- AIN. Although Ki-67 discriminated AIN and p16 HGAIN, E4/p16 staining shows that most AIN2 is different from transformed AIN3 in showing both entry into productive HPV infection and transforming activity.

Anal cytology in women: Experience from a single tertiary center

INTRODUCTION

Anal cytology (AC) can be used as a screening tool for detection of anal HPV associated lesions, mainly in men who have sex with men and in immunosuppressed patients. Our aim is to review our experience with AC in women.

MATERIAL & METHODS

We have retrospectively reviewed all AC diagnosed between 2010-2017 in a single tertiary hospital (n = 644) and selected those performed in women (n = 158).

RESULTS

24.53% of AC were performed in women. 14.7% of all women were HIV positive and 56.7% referred anal intercourse. Squamous lesions were found in 27.2% of women, most of them ASCUS and LSIL (14% and 11.5%). HPV DNA was detected in 38.6% of patients, and 63.9% of them showed positivity for multiple high-risk types. Anal biopsy showed high grade lesions in 20% of biopsied patients. We observed a significant relationship between HPV status and receptive anal sex, and the association between HPV status and anal histological diagnosis tended to significance. Sensitivity, specificity, negative predictive value and positive predictive value for anal cytology were 57%; 83%; 28% and 94%, respectively. 70.9% of women had synchronous cervical cytology, and squamous cervical lesions were detected in 46.4% of the cases, most of them LSIL or ASCUS (21.4% and 15.2%). We did not confirm a significant association between cytological diagnosis of cervical and anal samples.

CONCLUSIONS

AC is less widely used in women than in homosexual men. However, women show important rates of anal lesions, regardless of their HIV status. More studies should be performed to assess the potential impact of screening protocols in this population.

Biomarker P16 predicts progression risk of anal low-grade squamous intraepithelial lesions

OBJECTIVES

The aim of this study was to determine whether biomarker P16 predicts progression risk for anal low-grade squamous intraepithelial lesions (LSILs).

DESIGN

A retrospective study.

METHODS

One hundred and nine HIV-infected and 18 HIV-uninfected patients with biopsy-proven anal LSIL at initial screening underwent surveillance high-resolution anoscopy and biopsy within 2 years of diagnosis. P16 immunohistochemistry was performed on index lesions and evaluated using a semi-quantitative scoring system. The association of predictors and lesional outcomes (progression, persistence or regression) was analysed using ordinal logistic regression models. A subset of p16-positive LSILs was tested for high-risk human papillomavirus (HR-HPV) DNA using real-time PCR.

RESULTS

Upon follow-up, 46 (36%) LSILs progressed to high-grade squamous intraepithelial lesion (HSIL), 50 (40%) persisted as LSIL and 31 (24%) regressed to benign mucosa (median 16 months, range 5-24 months). Age, sex, race, history of condylomata, CD4 T-cell count and HIV plasma viral load were similar regardless of clinical outcome. P16 immunoreactivity of index lesion was classified as block-positive (n = 36), focal-positive (n = 49) or negative (n = 42). Sixty-four percent of block-positive lesions progressed, as opposed to 35% of focal-positive and 14% of negative lesions (P < 0.001). HR-HPV DNA was detected in 90% of p16 block-positive lesions vs. 55% of focal-positive lesions. In unadjusted analyses, positive p16, HIV and former smoker status were significantly associated with lesional persistence and progression. P16 remained the only significant predictor in an adjusted model.

CONCLUSION

Biomarker p16 is the strongest predictor for anal LSIL-to-HSIL progression, outperforming other risk factors. To enhance the overall effectiveness of surveillance, we propose using p16 immunohistochemistry to help stratify patients at high vs. low risk of progression.

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

p16 is the most widely studied biomarker in lower anogenital tract squamous intraepithelial lesions and, currently the only recommended biomarker for histological grade assessment. The aim of this systematic review and meta-analysis was to evaluate p16-positive rates according to anal squamous intraepithelial lesions/anal intraepithelial neoplasia (AIN) grade. Two investigators independently searched four electronic databases: PubMed, Web of Sciences, Scopus, and Embase from inception until August 2017. Studies that evaluated p16 immunostaining in histological samples of anal and/or perianal squamous intraepithelial lesions and defined a p16-positive result as diffuse block staining with nuclear or nuclear plus cytoplasmic staining were included. A meta-analysis was performed using a random effects model. Fifteen studies consisting of 790 samples were included. The proportion of p16 expression increased with the severity of histological grade. p16 positivity was 2% (95% CI: 0.2-5%) in normal histology, 12% (95% CI: 2-27%) in low-grade squamous intraepithelial lesions (LSILs)/AIN1 (excluding condylomas), 7% (95% CI: 2-13%) in all LSIL (AIN1/LSIL/condyloma), 76% (95% CI: 61-88%) in AIN2, and 90% (95% CI: 82-95%) in AIN3. For anal high-grade squamous intraepithelial lesions (HSILs), in studies using a two-tiered nomenclature, p16 positivity was 84% (95% CI: 66-96%) and for all HSIL (AIN2, AIN3, HSIL combined) it was 82% (95% CI: 72-91%). In summary, p16 positivity in anal squamous intraepithelial lesions appears to be in a similar range to the commonly described cervical squamous intraepithelial lesions, however, for anal low-grade lesions positivity seems to be lower.

Multiple epidermolytic acanthomas mimicking condyloma: a retrospective study of 8 cases

BACKGROUND

Epidermolytic acanthoma (EA) is an uncommon benign cutaneous lesion. Multiple epidermolytic acanthomas (multiple EAs) are rarely reported.

METHODS

We retrospectively identified patients diagnosed with multiple EAs between 2005 and 2017 from our dermatopathology database and analyzed their clinical, pathological, and immunohistochemical features. We also evaluated the association of multiple EAs with human papillomavirus (HPV) infection.

RESULTS

In total, eight patients (average age 51 years; 3 : 1 male predominance) with multiple EAs were found. All patients had lesions on the genitocrural area. The two most common clinical diagnoses were condyloma (5/8) and soft fibroma (3/8), which were predominantly skin-colored (5/8) or whitish (2/8). The lesions were less than 1 cm in diameter, and most (6/8) appeared to have a smooth surface. No molecular evidence suggesting HPV infection was found. Immunohistochemical staining showed low mitotic activity. The lesions were removed in one of two patients via cryotherapy, and one patient was treated with electrocauterization. The other five patients were followed without treatment.

CONCLUSION

The genital area was the most common location for multiple EAs, which was commonly misdiagnosed clinically as condyloma. Patients presenting with uniformly small-sized, skin-colored to whitish, smooth papular lesions in the genitalia should be carefully evaluated. The specific pathological features of epidermolytic hyperkeratosis are diagnostic, and the lesions can be observed without aggressive treatment after confirmed diagnosis.

Poroid Condyloma Versus Poroma With Atypias Because of Human Papillomavirus Infection

We present the case of a 43-year-old white man with a complex lesion at the base of the penis that combines features of both a poroma and a condyloma with human papillomavirus (HPV) infection, atypias, and focal ductal differentiation. It was a papillomatous lesion with epidermal hyperplasia, which mainly contained focally pigmented monotonous basaloid cells. Ductal lumina with cuticular cells were easily identified. Atypias were focally evidenced, with nuclear enlargement and hyperchromasia. Hypergranulosis and koilocytosis were also present. Immunohistochemical studies indicated p16 and p53 immunoexpression in the areas with cellular atypia and koilocytosis. Studies with in situ hybridization showed positivity for HPVs 16/18 and 31/33 in such areas, with a high rate of proliferation indicated by Ki-67. There was no positivity for HPV 6/11. Epithelial membrane antigen highlighted the ductal lumina, whereas there was no immunostaining for carcinoembryonic antigen.

Proposed Terminology for Anal Squamous Lesions: Its Application and Interobserver Agreement Among Pathologists in Academic and Community Hospitals

OBJECTIVES

To analyze interobserver reproducibility and compare practice patterns between academic and community settings of Lower Anogenital Squamous Terminology (LAST).

METHODS

In total, 132 anal biopsy slides were revised as well as p16 immunostains.

RESULTS

LAST was used in 49% of cases (academic center, 68%; satellite hospitals [community practice setting], 32%). After pathology review and consensus interpretation, 23 (17%) case diagnoses were reclassified: eight (34.8%) cases (benign or low-grade squamous intraepithelial lesion [LSIL]) were upgraded to high-grade squamous intraepithelial lesion (HSIL) (p16 confirmed ordered during review); four (17.4%) cases originally classified as HSIL were downgraded to LSIL (p16 originally ordered in one case). There was no significant difference in discrepancies between original and consensus diagnosis in the community vs academic setting or by subspecialty (gynecological vs gastrointestinal). Overall interobserver agreement among reviewers was substantial (κ = 0.63) and improved with the use of p16 immunostain in challenging cases (κ = 0.71; P < .001).

CONCLUSIONS

This new terminology is not yet uniformly used by pathologists in anal/perianal biopsy specimens; this two-tier system has a good interobserver agreement and is further improved with p16 use in appropriate cases.

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.

p16 immunostaining as a predictor of anal and cervical dysplasia in women attending a sexually transmitted infection clinic

BACKGROUND

Carcinogenesis caused by human papillomavirus (HPV) leads to over-expression of p16 protein. p16 may act as a marker of HPV integration with host genome and serve as a surrogate marker of HPV oncogenesis.

MATERIALS AND METHODS

A single center study of 75 women (35 HIV-positive and 40 HIV-negative women) was conducted. Anal and cervical specimens were obtained for cytology and p16 immunostaining.

RESULTS

The sensitivity of p16 to diagnose anal and cervical dysplasia was 50% and 58.8%, respectively, whereas specificity was 98.6% and 100%, respectively. Positive predictive value for anal and cervical was 75% and 100%, whereas negative predictive value was 95.8% and 89.2%, respectively. A strong relationship between the grade of dysplasia and intensity of p16 immunoscore was observed (Pearson correlation r = 0.666, P < 0.0001 and r = 0.496, P < 0.0001 for anal and cervical, respectively).

CONCLUSION

p16 immunostaining with greater specificity for high-grade lesions may improve the diagnostic accuracy, especially for high-grade lesions which have a high risk of progression to malignancy and thereby necessitate treatment.

Seborrheic keratosis with bowenoid transformation: the immunohistochemical features and its association with human papillomavirus infection

The bowenoid transformation of seborrheic keratosis (SK) has rarely been reported. The purpose of this study is to identify their diagnostic immunohistochemical features and association with human papillomavirus (HPV) infection. Skin biopsy specimens of the phenomenon were retrieved from 2001 to 2010. Benign SK, Bowen disease, bowenoid papulosis, and squamous cell carcinoma were included as controls. All specimens were stained for hematoxylin and eosin, Ki-67, p21, p16, p53, and cyclin D1. Polymerase chain reaction-amplified HPV DNA was analyzed. Seventeen cases of SK with bowenoid transformation were identified. The immunohistochemical pattern of bowenoid transformation was similar to that of Bowen disease and bowenoid papulosis. The malignant cells exhibited increased expressions of p16, p21, and ki-67 and a decreased expression of cyclin D1 (P < 0.01). HPV DNA was detected in 5 cases of bowenoid transformation. In conclusion, a portion of the cases of SK with bowenoid transformation were associated with HPV infection. Selective immunohistochemical stains were helpful in the diagnosis of malignant change in these cases.

An update on anal neoplasia

Although anal cancer remains a relatively uncommon tumour its frequency is rising, especially in high-risk groups. It is now well recognized that anal squamous cell carcinoma, the largely predominant tumour type, shares many similarities with cancer of the uterine cervix, with a major role for oncogenic human papilloma viruses in both tumours. Anal squamous precancerous lesions have now to be classified with the same criteria and terminology as their cervical counterparts, by using the Lower Anogenital Squamous Terminology (LAST) proposal. Only p16 protein is a useful marker in this setting at the present time. As most cases of anal cancer are treated by non-surgical procedures, pathology has a limited role in the staging of the disease, except for early lesions treated by local excision, and when the sentinel lymph node procedure is undertaken that is still under evaluation. A variety of other tumour types can occur more rarely, with difficult diagnostic issues, solved in most cases by immunohistochemistry.

Keratoacanthoma of the Lip: Activation of the mTOR Pathway, Tumor Suppressor Proteins, and Tumor Senescence

The PI3K-PTEN-mTOR is one of the most important pathways involved in cancer development and progression; however, its role in keratoacanthoma (KA) is poorly understood. In this study, we investigated the activation of key proteins in the PI3K-mTOR pathway in lip KA. We analyzed the activation of the PI3K-PTEN-mTOR pathway using human tumor samples stained for well-established protein markers in this pathway, including pS6 and pAKT phosphoproteins. We assessed proliferation using Ki-67 and performed additional morphological and immunohistochemical analysis using anti-PTEN and anti-p16 antibodies.We found that the majority of KA labeled to pS6 and not pAKT. PTEN expression was inversely correlated with Ki-67 expression. In addition to PTEN expression, KA cells were positive for p16 senescence marker. PI3K-PTEN-mTOR pathway is activated in lip KA, leading to downstream activation of mTORC1, but not mTORC2. This pathway plays an important role in KA progression by promoting proliferation and activation of oncogenic-induced senescence.

Utility of Human Papillomavirus Capsid Protein L1 and p16 in the Assessment and Accurate Classification of Anal Squamous Intraepithelial Lesions

OBJECTIVES

Morphologic evaluation of anal dysplasia remains problematic, especially in cases with limited biopsy samples or obscuring inflammation. Studies in cervical neoplasia have shown that human papillomavirus (HPV) L1 capsid production is highest in low-grade squamous intraepithelial lesions (LSILs) and progressively decreases in high-grade squamous intraepithelial lesions (HSILs). The combined utility of HPV L1 and p16 expression in assessing anal squamous intraepithelial lesions (SILs) has never been analyzed and forms the basis of this study.

METHODS

In total, 145 anal lesions were reviewed and immunohistochemically stained for HPV L1 and p16. p16 expression was recorded as negative, patchy/focal, or diffuse. For analytical purposes, condylomas were evaluated separately from rest of the LSILs.

RESULTS

There were 34 (23%) condylomas, 64 (44%) LSILs, and 47 (32%) HSILs. HPV L1 was significantly associated with condylomas (68%) and LSILs (52%) compared with HSILs (9%; P < .0001). Diffuse p16 staining was present only in HSILs (P < .0001), whereas a patchy/focal p16 staining pattern was observed in both LSILs and condylomas.

CONCLUSIONS

HPV L1 and diffuse p16 expression is mutually exclusive in most anal SILs and helps separate LSIL and HSIL cases. Application of both HPV L1 and p16 can not only facilitate accurate grading but also contribute to risk assessment in anal neoplasia.

p16 is superior to ProEx C in identifying high-grade squamous intraepithelial lesions (HSIL) of the anal canal

Although the incidence of human papillomavirus (HPV)-associated anal neoplasia is increasing, interobserver and intraobserver reproducibility in the grading of biopsy specimens from this area remains unacceptably low. Attempts to produce a more reproducible grading scheme have led to the use of biomarkers for the detection of high-risk HPV (HR-HPV). We evaluated the performance of standard morphology and biomarkers p16, ProEx C, and Ki-67 in a set of 75 lesions [17 nondysplastic lesions, 23 low-grade squamous intraepithelial lesions (LSIL)/condyloma, 20 high-grade squamous intraepithelial lesions (HSIL), 15 invasive squamous cell carcinomas] from the anal and perianal region in 65 patients and correlated these findings with HPV subtype on the basis of a type-specific multiplex real-time polymerase chain reaction assay designed to detect HR-HPV. A subset of cases with amplifiable HPV DNA was also sequenced. HSIL was typically flat (15/20), and only a minority (4/20) had koilocytes. In contrast, only 1 LSIL was flat (1/23), and the remainder were exophytic. The majority of LSIL had areas of koilocytic change (20/23). HR-HPV DNA was detected in the majority (89%) of invasive carcinomas and HSIL biopsies, 86% and 97% of which were accurately labeled by strong and diffuse block-positive p16 and ProEx C, respectively. LSIL cases, however, only infrequently harbored HR-HPV (13%); most harbored low-risk HPV (LR-HPV) types 6 and 11. Within the LSIL group, p16 outperformed ProEx C, resulting in fewer false-positive cases (5% vs. 75%). Ki-67 was also increased in HR-HPV-positive lesions, although biopsies with increased inflammation and reactive changes also showed higher Ki-67 indices. These data suggest that strong and diffuse block-positive nuclear and cytoplasmic labeling with p16 is a highly specific biomarker for the presence of HR-HPV in anal biopsies and that this finding correlates with high-grade lesions.

The reporting of anal cytology and histology samples: establishing terminology and criteria

Our understanding of the human papillomavirus (HPV) related cytomorphology and histopathology of the anal canal is underpinned by our knowledge of HPV infection in the cervix. In this review, we utilise cervical reporting of cytological and histological specimens as a foundation for the development of standardised and evidence-based terminology and criteria for reporting of anal specimens. We advocate use of the Australian Modified Bethesda System 2004 for reporting anal cytology. We propose the use of a two-tiered histological reporting system for noninvasive disease – low-grade and high-grade anal intraepithelial neoplasia. These classification systems reflect current understanding of the biology of HPV and enhance diagnostic reproducibility. Biomarkers such as p16INK4A may prove useful in further improving diagnostic accuracy. Standardisation is important because it will increase the value of the data collected as Australian centres develop programs for screening for anal neoplasia.

An update on tumors of the anal canal

CONTEXT

The anal canal possesses complex anatomy and histology and gives rise to a variety of tumor types. Challenging issues remain with regard to both the pathologic diagnosis and the clinical management of these tumors.

OBJECTIVES

To provide an updated overview of the histogenesis, clinical and pathologic characteristics, diagnostic terminology, and relevant clinical management of the various types of anal canal tumors.

DATA SOURCES

Recent literature on clinical and pathologic characteristics of anal canal tumors.

CONCLUSIONS

Although most anal canal tumors are of squamous lineage, a complex variety of other tumors also occurs. Recognition of such diverse tumor entities will allow accurate pathologic diagnosis and most optimal clinical management.

P16/CDKN2A and Ki-67 enhance the detection of anal intraepithelial neoplasia and condyloma and correlate with human papillomavirus detection by polymerase chain reaction

The classification of anal intraepithelial neoplasia (AIN) in mucosal biopsies is subject to considerable interobserver variability. Previous studies have shown that Ki-67 and p16/CDKN2A immunostains aid detection of dysplasia in biopsy samples from the uterine cervix. The aim of this study was to determine whether Ki-67 and p16/CDKN2A immunolabeling enhanced diagnostic accuracy in the assessment of anal mucosal biopsies from patients with suspected human papillomavirus (HPV) infection. The study consisted of 75 cases that were originally interpreted to represent normal anal transitional zone (n=15), fibroepithelial polyp (n=10), condyloma accuminatum (n=10), low-grade AIN (AIN1, n=20), and high-grade AIN (n=20), including 10 cases each of AIN2 and AIN3. The histologic features of all cases were re-reviewed and categorized based upon consensus agreement, which resulted in reclassification of 16 cases. Thus, the final study group consisted of 17 samples of normal anal transition zone, 14 fibroepithelial polyps, 6 condylomata accuminata, and 38 cases of AIN (11 AIN1, 16 AIN2, and 11 AIN3). Each case was tested for the presence of HPV DNA by a SPF10 polymerase chain reaction and LiPA25 genotyping assay and immunostained for Ki-67 and p16/CDKN2A. A positive Ki-67 result was defined as the presence of a cluster of at least 2 strongly stained epithelial nuclei in the upper two-thirds of the epithelial thickness. A positive result for p16/CDKN2A was defined as diffuse moderate-to-strong cytoplasmic and nuclear staining. None of the anal transition zone samples or fibroepithelial polyps showed Ki-67 or p16/CDKN2A staining. All condylomata and samples of AIN contained HPV DNA and showed positive Ki-67 labeling. All cases of high-grade AIN showed positive p16/CDKN2A staining. We conclude that Ki-67 labeling detects anal HPV-related changes with a high degree of sensitivity and specificity, whereas increased p16/CDKN2A staining is strongly associated with high-grade squamous neoplasia. These results indicate that a combination of these markers may aid interpretation of anal mucosal biopsy samples.

Expression of proliferative biomarkers in anal intraepithelial neoplasia of HIV-positive men

BACKGROUND

Anal intraepithelial neoplasia (AIN), a human papillomavirus (HPV)-associated precursor lesion of anal carcinoma, is highly prevalent among HIV-infected individuals, especially in men having sex with men (MSM). Early diagnosis and treatment of AIN might prevent development of anal cancer.

OBJECTIVES

We aimed to evaluate the expression of 8 promising proliferative biomarkers in anal dysplasia and to compare the efficacy of these markers in diagnosing high-grade AIN.

METHODS

Immunohistochemical analysis of minichromosome maintenance proteins (MCM3, MCM4, MCM6, and MCM7), p21, Ki-67, p16, and proliferating cell nuclear antigen (PCNA) was performed in a total of 49 specimens of normal anal mucosa and high- and low-grade anal dysplasia. HPV typing for 36 high- and low-risk HPVs was performed, and high-risk HPV-DNA loads were determined by real-time polymerase chain reaction (PCR) for HPV-types 16, 18, 31, and 33.

RESULTS

A total of 392 immunohistochemical slides were analyzed in this study. In the progression from normal epithelium to high-grade dysplasia, we found significant differences in the expression of all biomarkers. A cutoff of 25% or 50% lesional immunopositivity for the 4 MCMs, Ki-67, and p16 resulted in 100% sensitivity and 100% specificity to diagnose high-grade AIN. Sensitivity and specificity of PCNA and p21 for a high-grade AIN diagnosis were lower. HPV-DNA was detectable in 100% of high-grade AIN and 87.5% of low-grade AIN lesions. All MCMs, p16, Ki-67, and PCNA, but not p21 correlated with cumulative lesional high-grade HPV-DNA loads.

LIMITATIONS

The relatively small number of samples is a limitation, especially for adequate subgroup analyses.

CONCLUSIONS

MCMs, Ki67, and p16 are reliable immunohistochemical adjuncts for diagnosing high-grade AIN.

Growth factor receptor expression in anal squamous lesions: modifications associated with oncogenic human papillomavirus and human immunodeficiency virus

High prevalence of squamous anal lesions is linked to oncogenic human papillomavirus (HPV). Human immunodeficiency virus (HIV) promotes anal carcinogenesis. Epidermal growth factor receptor (EGFR), HER2/neu, c-Met, and vascular endothelial growth factor receptor-1 (VEGFR1) (tyrosine kinase growth factor receptors) are implicated in tumor progression, but little is known about their role in anal lesions. We investigated their expression and distribution in normal, dysplastic, and carcinomatous anal epithelium and then tried to analyze the effects on these variables of HPV and the HIV-positive status. Seventy-one HIV-positive and 47 HIV-negative patients were selected. We studied growth factor receptors, p16 and Ki67 expression, by in situ hybridization, fluorescent in situ hybridization (FISH) and chromogen in situ hybridization (CISH), immunocytochemistry, and morphological quantification in 226 lesions, either infected by HPV6 and 11 (31 condylomas acuminata) or infected with oncogenic HPVs (48 invasive cancers, 147 anal intraepithelial neoplasias). No HER2/neu was detected. Strong EGFR immunolabeling was not accompanied by gene amplification. The number and intensity of EGFR- and c-Met-immunoreactive cells increased significantly during lesion progression, highlighting the effects of oncogenic HPVs. EGFR, c-Met, VEGFR1, and p16 were coexpressed in 96% of invasive cancers. HIV-modified c-Met expression in condyloma acuminata (P < .008) and invasive cancers (P < .02). Strong HIV-related immunodeficiency and an absence of antiretroviral therapy increased c-Met and/or EGFR expression. HIV-positive anal cancers showed correlated c-Met and VEGFR1 (P < .003), strong p16 labeling, and an increased Ki67 proliferation. The finding that EGFR, c-Met, and VEGFR1 involved in carcinogenesis are well-represented and coexpressed in anal cancers, especially in HIV-positive population, suggests possible novel targeted treatments for anal diseases.

Screening for HIV-associated anal cancer: correlation of HPV genotypes, p16, and E6 transcripts with anal pathology

BACKGROUND

HIV-positive men with a history of anal-receptive intercourse are at risk for anal cancer. We determined whether human papilloma virus (HPV) biomarkers were correlated with anal pathology in these men.

METHODS

HPV genotype was determined by PCR/line blot assay. Real-time PCR assays were done for viral load, E6 transcripts for HPV genotypes 16, 18, and 31, and p16 transcripts.

RESULTS

The most common oncogenic HPV types were HPV 16 (38%), 18 (19%), 45 (22%), and 52 (19%). HPV types 16, 18, 31, 52, 59, and 68 were associated with high-grade histology. The number of HPV genotypes per anal swab was higher for anal intraepithelial neoplasia (AIN) 2/3 than for normal or AIN 1 histology [median, 5 types (interquartile range) (IQR), 3-7 versus 3.5 (IQR), 2-6; P = 0.0005]. HPV 16 viral load was also associated with AIN 2/3 histology. There was no difference in p16 or E6 transcripts between histologic grades. In the multivariable logistic regression model, HPV genotypes 16 [odds ratio, 2.58; 95% confidence interval (95% CI), 1.31-5.08; P = 0.006] and 31 (odds ratio, 4.74; 95% CI, 2.00-11.22; P = 0.0004), baseline CD4 count < 400 cells/mm(3) (odds ratio, 2.96; 95% CI, 1.46-5.99; P = 0.0025), and Acquired Immunodeficiency Syndrome (AIDS)-defining illness (odds ratio, 2.42; 95% CI, 1.22-4.82; P = 0.01) were associated with high-grade histology after adjusting for age.

CONCLUSIONS

The presence of high-grade anal pathology (AIN 2/3) in HIV-positive men was associated with multiple HPV genotypes, HPV genotypes 16 and 31, and HPV 16 viral load.

Most basal-like breast carcinomas demonstrate the same Rb-/p16+ immunophenotype as the HPV-related poorly differentiated squamous cell carcinomas which they resemble morphologically

Basal-like carcinomas (BLCs) of the breast share discriminatory morphologic features with poorly differentiated high-risk human papilloma virus (HPV)-related squamous cell carcinomas of the oropharynx, penis, and vulva. Because HPV E7 protein inactivates the retinoblastoma (Rb) protein, diffuse p16 expression is a surrogate marker for these high-risk HPV-related carcinomas. HPV E6 protein also inactivates p53, further compromising the G1-S cell cycle checkpoint. The Rb/p16/p53 immunohistochemical profile of BLC of the breast has not been well characterized. Tissue microarrays containing 71 invasive ductal carcinomas (IDCs) of the breast were immunolabeled for p16, Rb, p53, and Ki-67. The cases included 4 distinct groups of IDCs having surrogate immunohistochemical profiles corresponding to categories defined by gene expression profiling (17 luminal A, 7 luminal B, 14 HER-2+, and 21 BLC), along with 12 unclassifiable triple negative carcinomas (UTNCs). Twenty-five of the 71 IDC were Rb negative/p16 diffuse positive (Rb-/p16+). These included 15 of 21 BLC and 9 of 12 UTNC, but only 1 of 14 HER-2 positive cases and none of the 17 luminal A or 7 luminal B cases (P<0.01, BLC or UTNC vs. others). Six of the Rb-/p16+ IDC also had a significant ductal carcinoma in situ component. The ductal carcinoma in situ in 4 of these 6 cases showed the same Rb-/p16+ phenotype as the associated IDC. BLC and UTNC had the highest Ki-67 indices of the 5 groups, even when matched for grade. The Rb-/p16+ phenotype and the Rb-/p16+/p53 overexpressing phenotype correlated with increased proliferation within the BLC group. In conclusion, BLC and UTNC, but not HER-2, luminal A, or luminal B carcinomas, frequently demonstrate an Rb-/p16+ phenotype, similar to the HPV-related squamous cell carcinomas that BLC resemble morphologically. This subset may represent a more homogenous group than BLC as defined currently.

Diagnostic problems in anal pathology

Anal squamous cell carcinoma and its precursor lesions are increasing in incidence in the United States and Europe. This trend predates human immunodeficiency virus/acquired immune deficiency syndrome and has been associated with persistent high-risk human papilloma virus (HPV) genotype infection, previous lower genital tract dysplasia/carcinoma, high frequency anoreceptive intercourse, heavy cigarette smoking, immunosuppression in solid organ transplant and immune disorders, and human immunodeficiency virus seropositivity. Screening protocols for at-risk patients are under active investigation and pathologists are often asked to assess anal canal and perianal biopsies for the presence of dysplasia and/or invasive carcinoma. Because underdiagnosis and overdiagnosis of anal cancer and precancer may lead to inappropriate treatment, it is important for the pathologist to be aware of current screening strategies, specific risk lesions, and the role of pathology in initial diagnosis and evaluation of anal biopsy and/or resection specimens. Standardized histologic criteria and uniform terminology should be used for reporting all anal canal and perianal squamous intraepithelial lesions. HPV subtyping, anal cytology, and recently identified biomarkers, such as p16 and Becton Dickinson ProEx C may provide additional information in problematic cases, but it is important to be aware of the limitations of these assays. HPV has been linked to all the major histologic subtypes of anal carcinoma (eg, basaloid, cloacogenic, transitional, etc.) and this association is strongest for anal canal lesions. With the possible exception of the microcystic pattern, histologic subtype does not seem to predict prognosis; and anal squamous cell carcinomas should be classified as either keratinizing or nonkeratinizing. Poorly differentiated squamous cell carcinomas have a worse prognosis and should be distinguished from poorly differentiated adenocarcinoma, melanoma, and neuroendocrine tumors. Very well differentiated squamous cell carcinoma with pushing margins (so-called giant condyloma of Buschke and Lowenstein) should be classified as verrucous carcinoma; this tumor shows aggressive local infiltration but does not metastasize. As all anal condylomata may harbor foci of high-grade dysplasia or invasive carcinoma, careful sectioning and complete histologic examination is required.

[Anal and anal margin tumors]

Tumors of the anal canal and anal margin are rare. They may raise specific problems for the pathologist. Benign tumors mainly consist of condylomas, cloacogenic polyps and fibro-epithelial polyps. Cancers are infrequent and consisted of well-differentiated squamous cell carcinoma, or poorly differentiated basaloid squamous cell carcinoma. The other malignant tumors are very rare.

Anal intraepithelial neoplasia and other neoplastic precursor lesions of the anal canal and perianal region

Anal cancer is rare and this helps to explain why anal pre-neoplastic conditions are poorly understood, especially with regard to their natural history and management. Anal intraepithelial neoplasia is closely linked to human papillomavirus infection and is particularly common in homosexuals and in immunosuppressed patients, especially those with HIV/AIDS. The high regression rates of low-grade anal intraepithelial neoplasia may simply reflect inconsistent pathologic reporting. Higher grades of anal intraepithelial neoplasia may remain static for long periods of time in immunocompetent patients, but those with HIV/AIDS show early and rapid malignant transformation. In general, most anal pre-neoplastic conditions are best diagnosed by biopsy and treated by surgical excision, although local recurrence is a problem. In anal Paget's disease, it is important to ascertain, at the time of diagnosis, whether it is due to a primary in-situ apocrine-type of neoplasia of the anus or if the disease is secondary to an invasive primary carcinoma of the rectum.