DNA methylation in anal intraepithelial lesions and anal squamous cell carcinoma

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.

Integrated analysis of tumor-associated macrophages and M2 macrophages in CRC: unraveling molecular heterogeneity and developing a novel risk signature

BACKGROUND

Emerging investigations have increasingly highlighted the critical role of tumor-associated macrophages (TAMs) and M2 macrophages in cancer development, progression, and metastasis, marking them as potential targets in various cancer types. The main objective of this research is to discover new biomarkers associated with TAM-M2 macrophages in colorectal cancer (CRC) and to dissect the molecular heterogeneity of CRC by combining single-cell RNA sequencing and bulk RNA-seq data.

METHODS

By utilizing weighted gene co-expression network analysis (WGCNA), we acquired TAM-M2-associated genes by intersecting TAM marker genes obtained from scRNA-seq data with module genes of M2 macrophages derived from bulk RNA-seq data. We employed least absolute shrinkage and selection operator (LASSO) Cox analysis to select predictive biomarkers from these TAM-M2-related genes. Quantitative polymerase chain reaction (qPCR) was employed to validate the mRNA expression levels of the genes identified in the screening. This led to the development of the TAM-M2-related signature (TAMM2RS). We also conducted functional and immune landscape analyses of different risk groups.

RESULTS

The combination of scRNA-seq and bulk RNA-seq analyses yielded 377 TAM-M2-related genes. DAPK1, NAGK, and TRAF1 emerged as key prognostic genes in CRC, which were identified through LASSO Cox analysis. Utilizing these genes, we constructed and validated the TAMM2RS, demonstrating its effectiveness in predicting survival in CRC patients.

CONCLUSION

Our research offers a thorough investigation into the molecular mechanisms associated with TAM-M2 macrophages in CRC and unveils potential therapeutic targets, offering new insights for treatment strategies in colorectal cancer.

Unraveling Emerging Anal Cancer Clinical Biomarkers from Current Immuno-Oncogenomics Advances

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy associated with high-risk human papillomavirus (HPV) and is currently one of the fastest-growing causes of cancer incidence and mortality in developed countries. Although next-generation sequencing technologies (NGS) have revolutionized cancer and immuno-genomic research in various tumor types, a limited amount of clinical research has been developed to investigate the expression and the functional characterization of genomic data in ASCC. Herein, we comprehensively assess recent advancements in "omics" research, including a systematic analysis of genome-based studies, aiming to identify the most relevant ASCC cancer driver gene expressions and their associated signaling pathways. We also highlight the most significant biomarkers associated with anal cancer progression, gene expression of potential diagnostic biomarkers, expression of therapeutic drug targets, and emerging treatment opportunities. This review stresses the urgent need for developing target-specific therapies in ASCC. By illuminating the molecular characteristics and drug-target expression in ASCC, this study aims to provide insights for the development of precision medicine in anal cancer.

Anal Cancer Screening and Prevention: Summary of Evidence Reviewed for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infection Guidelines

In June 2019 the Centers for Disease Control and Prevention (CDC) convened an advisory group to assist in development of the 2021 CDC sexually transmitted infections (STI) guidelines. The advisory group on anal cancer screening and prevention met to formulate key questions in this field. The group examined published literature and abstracts to assess evidence and give recommendations for development of the CDC guidelines. This article summarizes key questions, evidence, recommendations, and areas for further research for the screening, diagnosis, and prevention of anal cancer.

Cancer Risk Stratification of Anal Intraepithelial Neoplasia in Human Immunodeficiency Virus-Positive Men by Validated Methylation Markers Associated With Progression to Cancer

Background

High-grade anal intraepithelial neoplasia (HGAIN; AIN2–3) is highly prevalent in HIV+ men, but only a minority of these lesions progress towards cancer. Currently, cancer progression risk cannot be established; therefore, no consensus exists on whether HGAIN should be treated. This study aimed to validate previously identified host cell DNA methylation markers for detection and cancer risk stratification of HGAIN.

Methods

A large independent cross-sectional series of 345 anal cancer, AIN3, AIN2, AIN1, and normal control biopsies of HIV+ men was tested for DNA methylation of 6 genes using quantitative methylation-specific PCR. We determined accuracy for detection of AIN3 and cancer (AIN3+) by univariable and multivariable logistic regression analysis, followed by leave-one-out cross-validation. Methylation levels were assessed in a series of 10 anal cancer cases with preceding HGAIN at similar anatomic locations, and compared with the cross-sectional series.

Results

Methylation levels of all genes increased with increasing severity of disease (P < .05). HGAIN revealed a heterogeneous methylation pattern, with a subset resembling cancer. ZNF582 showed highest accuracy (AUC = 0.88) for AIN3+ detection, slightly improved by addition of ASCL1 and SST (AUC = 0.89), forming a marker panel. In the longitudinal series, HGAIN preceding cancer displayed high methylation levels similar to cancers.

Conclusions

We validated the accuracy of 5 methylation markers for the detection of anal (pre-) cancer. High methylation levels in HGAIN were associated with progression to cancer. These markers provide a promising tool to identify HGAIN in need of treatment, preventing overtreatment of HGAIN with a low cancer progression risk.

DNA methylation markers have universal prognostic value for anal cancer risk in HIV-negative and HIV-positive individuals

Anal cancer has increasing incidence and is preceded by high‐grade anal intraepithelial neoplasia (HGAIN; AIN2–3). Previously, we identified and validated several methylation markers for accurate detection of anal cancer and HGAIN with cancer risk in HIV‐positive (HIV+) men who have sex with men (MSM). This study aimed to evaluate these markers in HIV‐negative risk groups. A cross‐sectional series of 176 tissue samples of anal cancer, AIN3, AIN2, AIN1 and control biopsies obtained in HIV‐negative women and men was tested for six methylation markers (ASCL1, LHX8, SST, WDR17, ZIC1 and ZNF582). Accuracy for detection of AIN3 and cancer (AIN3+) was determined by univariable and multivariable mixed‐effect ordinal logistic regression. Methylation levels of all markers increased with increasing severity of disease (P < 0.0001) and were comparable to results in HIV+ MSM. All markers showed high accuracy for AIN3+ detection [area under the curve (AUC): 0.83–0.86]. The optimal marker panel (ASCL1 and ZIC1; AUC = 0.85 for AIN3+) detected 98% of cancers at 79% specificity. In conclusion, DNA methylation markers show a high diagnostic performance for AIN3+ detection in HIV+ and HIV‐negative risk groups, justifying broad application of methylation analysis for anal cancer prevention programmes.

Pilot Study of Markers for High-grade Anal Dysplasia in a Southern Cohort From the Women's Interagency Human Immunodeficiency Virus Study

BACKGROUND

Anal cancer rates have increased, particularly in human immunodeficiency virus (HIV)-infected (HIV+) women. We assessed factors associated with anal precancer in HIV+ and at-risk HIV-negative women from the Atlanta Women's Interagency HIV Study cohort.

METHODS

All participants underwent high-resolution anoscopy and anal cytology and had anal and cervical samples collected. Specimens were tested for 37 human papillomavirus (HPV) types and for FAM19A4 and microRNA124-2 promoter methylation. Binary logistic regression and multivariate analysis were conducted with histologic anal high-grade squamous intraepithelial lesion (A-HSIL) as the dependent variable.

RESULTS

Seventy-five women were enrolled: 52 (69%) were HIV+ with three-fourths having undetectable viral load; 64 (86%) were black; mean age was 49 ± 8 years. Forty-nine (65%) anal cytology samples were abnormal, and 38 (51%) of anal samples were positive for at least 1 of 13 high-risk HPV (hrHPV) types. Thirteen (18%) anal biopsies identified A-HSIL. Hypermethylation of FAM19A4 and/or microRNA124-2 was found in 69 (95%) anal samples and 19 (26%) cervical samples. In multivariate analyses, the odds of having A-HSIL were >6 times higher in women with anal hrHPV (adjusted odds ratio [aOR], 6.08 [95% confidence interval {CI}, 1.27-29.18], P = .02) and with positive cervical methylation (aOR, 6.49 [95% CI, 1.66-25.35], P = .007), but not significantly higher in women with positive anal methylation.

CONCLUSIONS

Anal hrHPV and promoter hypermethylation in the cervix show promise as biomarkers for anal cancer screening in HIV+ and at-risk HIV-negative women. Greater understanding of gene silencing by promoter hypermethylation in anal carcinogenesis is needed.

Host Cell Deoxyribonucleic Acid Methylation Markers for the Detection of High-grade Anal Intraepithelial Neoplasia and Anal Cancer

Background

High-grade anal intraepithelial neoplasia (AIN2/3; HGAIN) is highly prevalent in human immunodeficiency virus positive (HIV+) men who have sex with men (MSM), but only a minority will eventually progress to cancer. Currently, the cancer risk cannot be established, and therefore all HGAIN is treated, resulting in overtreatment. We assessed host cell deoxyribonucleic acid (DNA) methylation markers for detecting HGAIN and anal cancer.

Methods

Tissue samples of HIV+ men with anal cancer (n = 26), AIN3 (n = 24), AIN2 (n = 42), AIN1 (n = 22) and HIV+ male controls (n = 34) were analyzed for methylation of 9 genes using quantitative methylation-specific polymerase chain reaction. Univariable and least absolute shrinkage and selection operator logistic regression, followed by leave-one-out cross-validation, were used to determine the performance for AIN3 and cancer detection.

Results

Methylation of all genes increased significantly with increasing severity of disease (P < 2 × 10^-6). HGAIN samples revealed heterogeneous methylation patterns, with a subset resembling cancer. Four genes (ASCL1, SST, ZIC1,ZNF582) showed remarkable performance for AIN3 and anal cancer detection (area under the curve [AUC] > 0.85). ZNF582 (AUC = 0.89), detected all cancers and 54% of AIN3 at 93% specificity. Slightly better performance (AUC = 0.90) was obtained using a 5-marker panel.

Conclusions

DNA methylation is associated with anal carcinogenesis. A marker panel that includes ZNF582 identifies anal cancer and HGAIN with a cancer-like methylation pattern, warrantingvalidation studies to verify its potential for screening and management of HIV+ MSM at risk for anal cancer.

Review: Anal Intraepithelial Neoplasia in HIV-Infected Men Who Have Sex with Men: Is Screening and Treatment Justified?

Anal squamous cell carcinoma (SCC) is the fourth most prevalent cancer in human immunodeficiency virus (HIV)-infected men who have sex with men (MSM). Human papillomavirus (HPV) has been detected in over 90% of anal carcinoma biopsy specimens from MSM, and is considered a necessary, but alone, insufficient factor for carcinogenesis. Anal intraepithelial neoplasia (AIN) may be precursive for SCC, and screening cytology with referral of persons with abnormality for high-resolution anoscopy-guided biopsy, and AIN treatment, has been recommended for prevention. In the absence of either randomized controlled trials or surveillance data demonstrating a reduction in anal SCC incidence, these recommendations were based on analogy with cervical cancer. HPV-mediated genetic changes associated with cervical cancer, and aneuploidy, have been documented in AIN. However, little data exist on the rate of AIN progression to SCC. The treatment of AIN is frequently prolonged and not curative, and if routinized in the care of HIV-infected MSM, would likely be recurring well into their sixth decade of life. Clinical trials demonstrating a reduction in invasive anal carcinoma incidence, as well as acceptable morbidity with repeated AIN destruction, are needed before asking our patients to commit to routine treatment.

Loss of histone variant macroH2A2 expression associates with progression of anal neoplasm

Aims

The macroH2A histone variants are epigenetic marks for inactivated chromatin. In this study, we examined the expression of macroH2A2 in anal neoplasm from anal intraepithelial neoplasia (AIN) to anal squamous cell carcinoma (SCC).

Methods

AIN and anal SCC samples were analysed for macroH2A2 expression, HIV and human papilloma virus (HPV). The association of macroH2A2 expression with clinical grade, disease recurrence, overall survival and viral involvement was determined.

Results

macroH2A2 was expressed in normal squamous tissue and lower grade AIN (I and II). Expression was lost in 38% of high-grade AIN (III) and 71% of anal SCC (p=0.002). Patients with AIN with macroH2A2-negative lesions showed earlier recurrence than those with macroH2A2-positive neoplasm (p=0.017). With anal SCC, macroH2A2 loss was more prevalent in the HPV-negative tumours.

Conclusions

Loss of histone variant macroH2A2 expression is associated with the progression of anal neoplasm and can be used as a prognostic biomarker for high-grade AIN and SCC.

Laser capture microdissection as a tool to evaluate human papillomavirus genotyping and methylation as biomarkers of persistence and progression of anal lesions

INTRODUCTION

Anal squamous cell carcinoma is preceded by persistent infection with high-risk human papillomavirus (HPV) and the cancer precursor, high-grade squamous intraepithelial lesion (HSIL). Detection of specific HPV genotypes and HPV-related biomarkers may be an option for primary anal screening. However, more data on the natural history of HPV-related anal lesions are required. The outcomes from this study will enhance our understanding of the clinical and biological behaviour of HPV-related anal lesions and inform the development of future HPV genotype and/or biomarker screening tests.

METHODS AND ANALYSIS

HIV-negative and HIV-positive men who have sex with men, aged 35 years and over, recruited from community-based settings in Sydney, Australia, attend 6 clinic visits over 3 years. At the first 5 visits, participants undergo a digital anorectal examination, an anal swab for HPV genotyping and anal cytology, and high-resolution anoscopy with directed biopsy of any visible abnormalities that are suggestive of any abnormality suspicious of SIL. Tissue sections from participants diagnosed with histologically confirmed HSIL at the baseline clinic visit will undergo laser capture microdissection, HPV detection and genotyping, and quantitation of CpG methylation in baseline and follow-up biopsies. Histological and cytological findings in combination with HPV genotyping data will be used to identify persistent HSIL. HSIL will be stratified as non-persistent and persistent based on their status at 12 months. The performance of HPV genotype and methylation status in predicting disease persistence at 12 months will be assessed, along with associations with HIV status and other covariates such as age.

ETHICS AND DISSEMINATION

The St Vincent's Hospital Ethics Committee granted ethics approval for the study. Written informed consent is obtained from all individuals before any study-specific procedures are performed. Findings from this study will be disseminated to participants and the community through study newsletters, and through peer-reviewed publications and international conferences.

Epigenomic characterization of locally advanced anal cancer: a radiation therapy oncology group 98-11 specimen study

BACKGROUND

The Radiation Therapy Oncology Group 98-11 clinical trial demonstrated the superiority of standard 5-fluorouracil/mitomycin-C over 5-fluorouracil/cisplatin in combination with radiation in the treatment of anal squamous cell cancer. Tumor size (>5 cm) and lymph node metastases are associated with disease progression. There may be key molecular differences (eg, DNA methylation changes) in tumors at high risk for progression.

OBJECTIVE

The objectives of this study were to determine whether there are differences in DNA methylation at individual CpG sites and within genes among locally advanced anal cancers, with large tumor size and/or nodal involvement, compared with those that are less advanced.

DESIGN

This was a case-case study among 121 patients defined as high risk (tumor size >5 cm and/or nodal involvement; n = 59) or low risk (≤5 cm, node negative; n = 62) within the mitomycin-C arm of the Radiation Therapy Oncology Group 98-11 trial. DNA methylation was measured using the Illumina HumanMethylation450 Array.

SETTINGS

The study was conducted in a tertiary care cancer center in collaboration with a national clinical trials cooperative group.

PATIENTS

The patients consisted of 74 women and 47 men with a median age of 54 years (range, 25-79 years).

MAIN OUTCOME MEASURES

DNA methylation differences at individual CpG sites and within genes between low- and high-risk patients were compared using the Mann-Whitney test (p < 0.001).

RESULTS

A total of 16 CpG loci were differentially methylated (14 increased and 2 decreased) in high- versus low-risk cases. Genes harboring differentially methylated CpG sites included known tumor suppressor genes and novel targets.

LIMITATIONS

This study only included patients in the mitomycin-C arm with tumor tissue; however, this sample was representative of the trial.

CONCLUSIONS

This is the first study to apply genome-wide methylation analysis to anal cancer. Biologically relevant differences in methylated targets were found to discriminate locally advanced from early anal cancer. Epigenetic events likely play a significant role in the progression of anal cancer and may serve as potential biomarkers.

DNA methylation profiling across the spectrum of HPV-associated anal squamous neoplasia

BACKGROUND

Changes in host tumor genome DNA methylation patterns are among the molecular alterations associated with HPV-related carcinogenesis. However, there is little known about the epigenetic changes associated specifically with the development of anal squamous cell cancer (SCC). We sought to characterize broad methylation profiles across the spectrum of anal squamous neoplasia.

METHODOLOGY/PRINCIPAL FINDINGS

Twenty-nine formalin-fixed paraffin embedded samples from 24 patients were evaluated and included adjacent histologically normal anal mucosa (NM; n = 3), SCC-in situ (SCC-IS; n = 11) and invasive SCC (n = 15). Thirteen women and 11 men with a median age of 44 years (range 26-81) were included in the study. Using the SFP(10) LiPA HPV-typing system, HPV was detected in at least one tissue from all patients with 93% (27/29) being positive for high-risk HPV types and 14 (93%) of 15 invasive SCC tissues testing positive for HPV 16. Bisulfite-modified DNA was interrogated for methylation at 1,505 CpG loci representing 807 genes using the Illumina GoldenGate Methylation Array. When comparing the progression from normal anal mucosa and SCC-IS to invasive SCC, 22 CpG loci representing 20 genes demonstrated significant differential methylation (p<0.01). The majority of differentially methylated gene targets occurred at or close to specific chromosomal locations such as previously described HPV methylation "hotspots" and viral integration sites.

CONCLUSIONS

We have identified a panel of differentially methlylated CpG loci across the spectrum of HPV-associated squamous neoplasia of the anus. To our knowledge, this is the first reported application of large-scale high throughput methylation analysis for the study of anal neoplasia. Our findings support further investigations into the role of host-genome methylation in HPV-associated anal carcinogenesis with implications towards enhanced diagnosis and screening strategies.

Gene methylation of SFRP2, P16, DAPK1, HIC1, and MGMT and KRAS mutations in sporadic colorectal cancer

The aim of this study was to investigate the methylation of the SFRP2, P16, DAPK1, HIC1, and MGMT genes, as well as the mutation of amino acid codons 12 and 13 of the KRAS gene in normal and tumor tissue DNA of patients diagnosed with sporadic colorectal cancer (SCRC). The methylation of gene regions and the KRAS mutations of normal (N) and tumor tissue (T) DNA obtained from 17 patients diagnosed with SCRC and 20 healthy controls were investigated using the polymerase chain reaction and reverse-hybridization methods. There was an Asp mutation in four patients, an Asp and Ser mutations in one patient in codon 12 of the KRAS gene, and an Asp mutation in codon 13 in eight patients. Overall promoter methylation (OPM) in the SFRP2 gene was observed in one N and four T, whereas partial promoter methylation (PPM) was observed in two N and five T. OPM in the P16 gene was present in one T. In the DAPK1 gene, OPM existed in seven T and five N, while PPM was present in two N. In the HIC1 gene, OPM was demonstrated in three T, while PPM was noted in two N; however, no methylation existed in N. In the MGMT gene, OPM occurred in five T and two N, and PPM was present in one T. KRAS mutations in Turkish patients with SCRC are similar to those of other population groups. Methylations in the genes, which underwent methylation analysis, were higher in T in comparison with N, and it has been suggested that significant results would be obtained by making a study with a larger population.

Demethylation treatment restores hic1 expression and impairs aggressiveness of head and neck squamous cell carcinoma

Promoter hypermethylation of tumor suppressor genes is a common feature of primary cancer cells. However, at date the somatic epigenetic events that occur in head and neck squamous cell carcinoma (HNSCC) tumorigenesis are not yet been well defined. In the present study we analysed the methylation status of the gene hypermethylated in cancer-1 (hic1), a gene located on chromosome 17p13.3, a region frequently lost in HNSCC. We analysed 22 HNSCC samples and three cell lines using methylation specific PCR (MSP). We found hic1 methylated in 21 out of 22 samples and in all three cell lines. Treatment of the cell lines with the demethylating agent 5-Azacytidin (5-Aza) resulted in the demethylation of the hic1 promoter and reactivation of hic1 expression as determined by MSP, qPCR and Western blot. Functional analyses revealed decreased proliferative activity and colony forming ability of treated cells. In summary, we found in HNSCC hic1 regulated by promoter methylation. 5-Aza application resulted in the reexpression of hic1 and was followed by decreased aggressiveness of the cancer cells. Our data indicate that hic1 might be a player in HNSCC development and suggest further evaluation of 5-Aza for HNSCC treatment.

Molecular biomarkers correlate with disease-free survival in patients with anal canal carcinoma treated with chemoradiation

Large primary tumor and clinical nodal involvement in patients with anal carcinoma treated with chemoradiation are associated with poor disease-free survival (DFS). However, the outcome in individual patient is unpredictable. We hypothesized that biomarkers related to chemotherapy and/or radiation resistance would be associated with DFS. We analyzed clinical and biomarker data in 30 patients with anal carcinoma who had chemoradiation. Patient selection was based on the availability of untreated cancer for biomarkers, completion of prescribed chemoradiation, and patient outcomes (~50% disease-free) nonrepresentative of published cohorts but conducive to biomarker discovery. Ten biomarkers, Ki67, human telomerase (hTERT), epidermal growth factor receptor (EGFR), p53, p16, Bcl-2, vascular endothelial growth factor (VEGF), nuclear factor kappa-B (NF-kappaB), SHH, and Gli-1, were studied. Raw data as continuous variable (only EGFR was trichotomized) were analyzed. Univariate and multivariate Cox models were utilized to assess relationship between DFS and biomarkers. Twenty-three of 30 patients were women, tumor diameter was >5 cm in 30, and 37% had clinically positive nodes. Fourteen (30%) patients had a DFS event after chemoradiation. In univariate analysis, NF-kappaB (P = 0.01), SHH (P = 0.02), Gli-1 (P = 0.02), and tumor diameter (P = 0.03) were significantly associated with DFS, and Ki67 (P = 0.07) was marginally significant. In multivariate analysis, tumor diameter (P = 0.003), Ki67 (P = 0.005), NF-kappaB (P = 0.002), SHH (P = 0.02), and Gli-1 (P = 0.02) were significantly associated with DFS. Our data, albeit preliminary, suggest that several biomarkers (Ki67, NF-kappaB, SHH, and Gli-1) are associated with DFS. Upon further expansion and validation, these results may provide a biomarker-based understanding of heterogeneous clinical biology of patients with anal carcinoma.

HIC1 regulates tumor cell responses to endocrine therapies

An intractable problem impeding breast cancer treatment by the most frequently prescribed endocrine therapy tamoxifen is the inevitable development of resistance, and the molecular mechanisms underlying this loss of responsiveness by breast cancers have been under intense investigation but are not yet fully elucidated. Our recent reports demonstrated that the tumor suppressor heavily methylated in cancers 1 (HIC1) plays an essential role in growth suppression mediated by external stimuli. We report here that novel tumor suppressor HIC1 is required for growth suppression by estrogen antagonists in breast cancer cells. We also find that HIC1 expression is dramatically induced by exposure to estrogen antagonists in sensitive cells, via a c-Jun N-terminal kinase 1 (JNK1) and prohibitin-mediated signaling pathway. This induction is lost in spontaneously antagonist-resistant breast cancer cells. Furthermore, reintroducing HIC1 into resistant breast cancer cells restored their sensitivity to the estrogen antagonists, indicating the existence of a novel regulatory mechanism for growth control of breast cancer cells.

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.

Current understanding and potential immunotherapy for HIV-associated squamous cell carcinoma of the anus (SCCA)

Squamous cell carcinoma of the anus (SCCA) is a rare disease in the average population but is an increasing concern among immunocompromised individuals, such as the HIV-seropositive. Coinfection with human papillomavirus (HPV) in this population is common. HPV infection is difficult to clear with a compromised immune system, which results in a greater risk of tumor development and a more aggressive progression of the disease. The recent approval of a prophylactic HPV vaccine for cervical cancer has sparked an interest in a search for improved immunotherapeutic multimodality therapies to combat anogenital tumors associated with the virus. In this review, we discuss the known mechanisms of action of HIV-associated SCCA, examine the current treatments for the disease, and focus on the potential of an immunotherapeutic vaccine approach for both prophylactic and therapeutic application.

Early involvement of death-associated protein kinase promoter hypermethylation in the carcinogenesis of Barrett's esophageal adenocarcinoma and its association with clinical progression

Esophageal Barrett's adenocarcinoma (BA) develops through a multistage process, which is associated with the transcriptional silencing of tumor-suppressor genes by promoter CpG island hypermethylation. In this study, we explored the promoter hypermethylation and protein expression of proapoptotic death-associated protein kinase (DAPK) during the multistep Barrett's carcinogenesis cascade. Early BA and paired samples of premalignant lesions of 61 patients were analyzed by methylation-specific polymerase chain reaction and immunohistochemistry. For the association of clinicopathological markers and protein expression, an immunohistochemical tissue microarray analysis of 66 additional BAs of advanced tumor stages was performed. Hypermethylation of DAPK promoter was detected in 20% of normal mucosa, 50% of Barrett's metaplasia, 53% of dysplasia, and 60% of adenocarcinomas, and resulted in a marked decrease in DAPK protein expression (P < .01). The loss of DAPK protein was significantly associated with advanced depth of tumor invasion and advanced tumor stages (P < .001). Moreover, the severity of reflux esophagitis correlated significantly with the hypermethylation rate of the DAPK promoter (P < .003). Thus, we consider DAPK inactivation by promoter hypermethylation as an early event in Barrett's carcinogenesis and suggest that a decreased protein expression of DAPK likely plays a role in the development and progression of BA.

Papillomavirus genome structure, expression, and post-transcriptional regulation

Papillomaviruses are a group of small non-enveloped DNA tumor viruses whose infection usually causes benign epithelial lesions (warts). Certain types of HPVs, such as HPV-16, HPV-18, and HPV-31, have been recognized as causative agents of cervical cancer and anal cancer and their infections, which arise via sexual transmission, are associated with more than 95% of cervical cancer. Papillomaviruses infect keratinocytes in the basal layer of stratified squamous epithelia and replicate in the nucleus of infected keratinocytes in a differentiation-dependent manner. Viral gene expression in infected cells depends on cell differentiation and is tightly regulated at the transcriptional and post-transcriptional levels. A noteworthy feature of all papillomavirus transcripts is that they are transcribed as a bicistronic or polycistronic form containing two or more ORFs and are polyadenylated at either an early or late poly(A) site. In the past ten years, remarkable progress has been made in understanding how this complex viral gene expression is regulated at the level of transcription (such as via DNA methylation) and particularly post-transcription (including RNA splicing, polyadenylation, and translation). Current knowledge of papillomavirus mRNA structure and RNA processing has provided some clues on how to control viral oncogene expression. However, we still have little knowledge about which mRNAs are used to translate each viral protein. Continuing research on post-transcriptional regulation of papillomavirus infection will remain as a future focus to provide more insights into papillomavirus-host interactions, the virus life-cycle, and viral oncogenesis.

Human papillomavirus-related tumors in HIV

PURPOSE OF REVIEW

Human papillomavirus-related anogenital cancers are theoretically preventable. Many HIV-infected women do not undergo routine cervical cytology screening, however, and there are currently no routine anal cytology screening programs. This review focuses on recent developments that may impact on the future incidence of these cancers: the effect of highly active antiretroviral therapy and the imminent approval of vaccines to prevent initial human papillomavirus infection.

RECENT FINDINGS

Highly active antiretroviral therapy has limited benefit to reduce the incidence of cervical intraepithelial neoplasia 3 and no benefit to reduce the incidence of anal intraepithelial neoplasia 3. Consistent with these findings, there has been no reduction in the incidence of cervical and anal cancer since the introduction of highly active antiretroviral therapy. More encouraging is the development of highly effective preventive human papillomavirus vaccines that are projected to reduce the incidence of cervical cancer by up to 70% among vaccinated women.

SUMMARY

HIV-positive men and women remain at risk for human papillomavirus-associated cancers, even in the highly active antiretroviral therapy era. Conversely, the incidence of anogenital cancers may decline in the future among HIV-positive individuals if they received the human papillomavirus vaccine before they acquired HIV infection, and studies should be done to assess the safety and efficacy of the vaccines in individuals already infected with HIV.