Human papillomavirus and cervical cancer in Indian women

The synergic effect of HPV infection and epigenetic anomaly of the p16 gene in the development of cervical cancer

BACKGROUND

Cervical cancer is the most common cancer in Indian women. Infection with a high-risk human papillomavirus (HR-HPV) is the greatest risk factor for developing cervical cancer. The genetic and epigenetic changes in the tumor suppressor p16 gene is play an important role in the development of cervical cancer.

OBJECTIVE

To evaluate the expression and promoter methylation of p16 gene in HR-HPV infected squamous cell carcinoma of the uterine cervix.

METHODS

To find out p16INK4a expression and methylation status 105 squamous cell carcinoma of the uterine cervix were investigated by using immunohistochemistry and Methylation Specific PCR techniques.

RESULTS

HPV16/18 was amplified in 83.8% cases of the cervix. 80% of them were positive for HPV type 16, while only 3.8% were positive for HPV type 18. Promoter CpG island hypermethylation of p16 gene was detected in 20.9% tissue samples of cervical carcinoma. Of these hypermethylated samples 90.9% cases showed nil/very low p16INK4a expression (P= 0.001). Overexpression of p16INK4a was observed in 73.3% cases of HR-HPV infected squamous cell carcinoma of the cervix.

CONCLUSION

An association between p16 methylation, expression, and HR-HPV infection suggested the compliance of HPV infection and aberration of p16 gene have a synergic effect on initiation and progression of cervical carcinoma.

Cervical Cancer Stem Cells Selectively Overexpress HPV Oncoprotein E6 that Controls Stemness and Self-Renewal through Upregulation of HES1

PURPOSE

Perturbation of keratinocyte differentiation by E6/E7 oncoproteins of high-risk human papillomaviruses that drive oncogenic transformation of cells in squamocolumnar junction of the uterine cervix may confer "stem-cell like" characteristics. However, the crosstalk between E6/E7 and stem cell signaling during cervical carcinogenesis is not well understood. We therefore examined the role of viral oncoproteins in stem cell signaling and maintenance of stemness in cervical cancer.

EXPERIMENTAL DESIGN

Isolation and enrichment of cervical cancer stem-like cells (CaCxSLCs) was done from cervical primary tumors and cancer cell lines by novel sequential gating using a set of functional and phenotypic markers (ABCG2, CD49f, CD71, CD133) in defined conditioned media for assessing sphere formation and expression of self-renewal and stemness markers by FACS, confocal microscopy, and qRT-PCR. Differential expression level and DNA-binding activity of Notch1 and its downstream targets in CaCxSLCs as well as silencing of HPVE6/Hes1 by siRNA was evaluated by gel retardation assay, FACS, immunoblotting, and qRT-PCR followed by in silico and in vivo xenograft analysis.

RESULTS

CaCxSLCs showed spheroid-forming ability, expressed self-renewal and stemness markers Oct4, Sox2, Nanog, Lrig1, and CD133, and selectively overexpressed E6 and HES1 transcripts in both cervical primary tumors and cancer cell lines. The enriched CaCxSLCs were highly tumorigenic and did recapitulate primary tumor histology in nude mice. siRNA silencing of HPVE6 or Hes1 abolished sphere formation, downregulated AP-1-STAT3 signaling, and induced redifferentiation.

CONCLUSIONS

Our findings suggest the possible mechanism by which HPVE6 potentially regulate and maintain stem-like cancer cells through Hes1. Clin Cancer Res; 22(16); 4170-84. ©2016 AACR.

A population-based study of the prevalence of HPV in three districts of Tamil Nadu, India

OBJECTIVE

To evaluate the prevalence of HPV infection among women from three districts of Tamil Nadu (Erode, Salem, and Namakkal).

METHODS

Between January 27, 2007, and December 15, 2009, 1800 women aged 20-70years who had normal cervical cytology were enrolled into a cross-sectional study. Participants completed interviews and provided first void urine samples for assessment of HPV infection.

RESULTS

Among 1699 eligible samples, 179 (10.5%) were HPV positive. HPV16 was the most common type (affecting 68 [4.0%] women), followed by HPV6 (58 [3.4%]). Among the 179 HPV-positive women, 71 (39.7%) were aged 36-45years. An annual income of less than 25 000 INR was significantly associated with HPV infection in all three districts (P<0.05). Regular intercourse was also associated with HPV in Erode and Salem (P<0.05).

CONCLUSION

Screening and prophylactic vaccines containing HPV16 and HPV6 should be promoted in western Tamil Nadu.

Koilocytosis: correlations with high-risk HPV and its comparison on tissue sections and cytology, urothelial carcinoma

The aim of this study were (1) To correlate koilocytosis with high risk HPV(HrHPV) DNA in urinary bladder carcinoma and (2) To compare detection of koilocytosis on tissue sections and urine cytology. Biopsy and cytologic specimens from 33 patients of urinary bladder carcinoma were analyzed. HPV DNA was detected by PCR on biopsy specimens using consensus primers MY09 and MY11. Koilocytosis was assessed both on tissue sections and urine cytology. HrHPV DNA was found in 14 of 33 bladder carcinoma. Koilocytosis was seen in tissue sections from 13 patients. Eleven of these were HrHPV DNA positive (positive predictive value 84.6%). Koilocytosis was seen in urine cytology in three patients. All three were positive for HrHPV DNA. To conclude koilocytosis is a good morphological marker for HrHPV DNA in the urothelium. Tissue sections are better than cytologic smears for detection of koilocytes.

Telomerase activity as an adjunct to high-risk human papillomavirus types 16 and 18 and cytology screening in cervical cancer

Telomerase is a ribonucleoprotein comprising an RNA template, the telomerase-associated protein and its catalytic subunit, human telomerase reverse transcriptase (hTERT). Telomerase activation is a critical step in cellular immortalisation and development of cancer. Enhanced telomerase activity has been demonstrated in cervical cancer. In the present study telomerase activity and hTERT mRNA expression were evaluated and correlated with the presence of human papillomavirus (HPV) infection and cytological changes in the cervical lesions. Telomerase activity was assayed by telomeric repeat amplification protocol, hTERT mRNA expression by reverse transcriptase polymerase chain reaction and presence of high risk HPV (HR-HPV) infection by polymerase chain reaction. Out of 154 cervical samples of different cytology, 90 (58.44%) were positive for HR-HPV types 16/18, while among 55 normal cervical scrapes, 10 (18.18%) were HPV DNA positive. All 59 invasive cancer samples showed a very high telomerase activity. Among dysplasia, seven (63.6%) mild dysplasia, 18 (100%) of moderate, 20 (100%) of severe dysplasia and 6 (100%) carcinoma in situ (CIS) samples were positive with mild to moderate to high to very high telomerase activity respectively. Seven (12.7%) samples of apparently normal cervical scrapes were weakly positive for telomerase activity. We observed a good correlation (P<0.001) between telomerase activity and HR-HPV 16/18 positivity with a sensitivity of 88.1% for HPV and 100% for telomerase activity. It is suggested that telomerase activity may be used as an adjunct to cytology and HPV DNA testing in triaging women with cervical lesions.

Human papillomavirus genotypes associated with cervical neoplasia in India

The aim of this study was to determine the prevalence of human papillomavirus (HPV) genotypes in tissue with cervical neoplasias in patients from south and east India. Cross-sectional cervical tissue was obtained from 100 patients from south India and 30 patients from east India who had a biopsy for clinically invasive cervical cancer or cervical intraepithelial neoplasia (CIN) in a tertiary care hospital in India. DNA amplification was done with biotinylated PGMY 09/11 primers, and the line blot assay was used to determine the HPV genotype. HPV DNA was detected in 95% of invasive cancers (113/119) and 91% of CINs (10/11). A single HPV type was found in 100 women (77%), and mixed infections were found in 23 women (18%). HPV 16 (60%) and HPV 18 (14%) were the most frequent types, but 16 other types (26, 31, 33, 35, 42, 45, 51, 52, 53, 56, 58, 61, 62, 64, 81, and 82) were also identified. HPV 16 was present in 63% of patients from south India and in 50% of patients from east India, while HPV 18 was present in 12% and 20%, respectively. There are several high-risk HPV types associated with cervical neoplasias of which types 16 and 18 are the most common.

Prevalence and distribution of high-risk human papilloma virus (HPV) types in invasive squamous cell carcinoma of the cervix and in normal women in Andhra Pradesh, India

BACKGROUND

Despite the high incidence of cervical cancer reported from India, large scale population based studies on the HPV prevalence and genotype distribution are very few from this region. In view of the clinical trials for HPV vaccine taking place in India, it is of utmost importance to understand the prevalence of HPV genotypes in various geographical regions of India. We investigated the genotype distribution of high-risk HPV types in squamous cell carcinomas and the prevalence of high-risk HPV in cervicovaginal samples in the southern state of Andhra Pradesh (AP), India.

METHODS

HPV genotyping was done in cervical cancer specimens (n = 41) obtained from women attending a regional cancer hospital in Hyderabad. HPV-DNA testing was also done in cervicovaginal samples (n = 185) collected from women enrolled in the cervical cancer screening pilot study conducted in the rural community, of Medchal Mandal, twenty kilometers away from Hyderabad.

RESULTS

High-risk HPV types were found in 87.8% (n = 36/41) of the squamous cell carcinomas using a PCR-based line blot assay. Among the HPV positive cancers, the overall type distribution of the major high-risk HPV types was as follows: HPV 16 (66.7%), HPV 18 (19.4%), HPV 33 (5.6%), HPV 35 (5.6%), HPV 45 (5.6%), HPV 52 (2.8%), HPV 58(2.8%), HPV 59(2.8%) and HPV 73 (2.8%). Women participating in the community screening programme provided both a self-collected vaginal swab and a clinician-collected cervical swab for HPV DNA testing. Primary screening for high risk HPV was performed using the Digene Hybrid Capture 2 (hc2) assay. All hc2 positive samples by any one method of collection were further analyzed using the Roche PCR-based line blot for genotype determination. The prevalence of high risk HPV infection in this community-based screening population was 10.3% (19/185) using the clinician-collected and 7.0% (13/185) using the self-collected samples. The overall agreement between self-collected and clinician-collected samples was 92%; however among HPV-positive specimens, the HPV agreement was only moderate (39.1%). The most frequently detected HPV types in the Medchal community are HPV 52 and 16.

CONCLUSION

Our results suggest that the HPV type distribution in both cervical cancer tissues and in a general screening population from Andhra Pradesh is similar to that reported in India and other parts of the world. We also conclude that an effective vaccine targeting HPV 16 will reduce the cervical cancer burden in AP.

Prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with cytologically negative Pap smear

OBJECTIVE

To study the prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with negative Pap smears in identifying women with underlying cervical squamous intra-epithelial (SIL) lesions.

METHODS

A total of 3300 women who were attending the Gynecology OPD of Lok Nayak Hospital, one of the major government tertiary hospitals in New Delhi, were screened during a 1-year study period, and 2079 (63%) of them were found to have cytologically negative Pap smear with inflammation and the rest (37%) also had negative Pap report but without inflammation. Hundred and sixty of these sexually active women aged between 20 and 60 years were randomly selected, and were investigated by colposcopy and a guided biopsy was done wherever required. HPV types 16 and 18 DNA was detected in scraped cervical cells from all women using type-specific primers in polymerase chain reaction (PCR).

RESULTS

The high-risk HPV (type 16 and 18) prevalence by PCR was found to be 10% (16/160). Histopathological findings were obtained in 123 women, out of which 15 had LSIL and four had HSIL. High-risk HPV types 16/18 could be detected in nine out of these 19 (47.3%) squamous intra-epithelial lesions (p < 0.00008) which includes two out of the four women (50%) having HSIL, while only seven out of 104 (6.7%) of the subjects with normal (negative) Pap reports (p = 0.03) had infection of high-risk HPV.

CONCLUSION

The results indicate that about 10% of women who show a negative Pap smear, but have inflammation are positive for high-risk HPV types 16/18 and about 15% harbor squamous intra-epithelial lesions. It is suggested that high-risk HPV detection can be utilized as an adjunct to routine cytology screening programs to identify 'high risk' women who have concurrently negative Pap smears but may harbor oncogenic HPV infection and/or more likely to develop CIN lesions.

Constitutive activation of transcription factor AP-1 in cervical cancer and suppression of human papillomavirus (HPV) transcription and AP-1 activity in HeLa cells by curcumin

The transcription factor AP-1 plays a central role in the transcriptional regulation of specific types of high-risk human papillomaviruses (HPVs) such as HPV16 and HPV18, which are etiologically associated with the development of cancer of the uterine cervix in women. In our study, we investigated the AP-1 binding activity and the expression pattern of different members of the AP-1 transcription factor family (c-Jun, JunB, JunD, c-Fos, FosB, Fra-1 and Fra-2) in different grades of cervical lesions starting from mild dysplasia to invasive cervical tumors, including normal control tissues, using specific antibodies raised against each of the AP-1 members. Results indicate that though AP-1 showed high binding activity and the majority of its members were highly expressed in tumor tissues, there is a distinct pattern of gradual increase of c-fos and a concomitant decrease of fra-1 expression that perfectly match the progression of cervical lesions. While c-fos is highly expressed in invasive cervical tumor, the expression of fra-1 becomes almost nil or absent, but the reverse is true in both controls and early precancerous lesions. These findings corroborate the results obtained in the cervical cancer cell line, HeLa. Interestingly, despite very low or absent AP-1 binding in normal as well as in premalignant lesions, AP-1 transcription and its binding activity was found to be very high in malignant tissues showing a preferential heterodimerization of c-fos with JunB instead of its canonical dimerization partner c-jun. Both in vivo and in vitro studies demonstrate that the overexpression of c-fos and downregulation of fra-1 expression as well as a change in the dimerization pattern of the AP-1 complex seem to play a crucial role during progression to malignancy. In a previous study, we demonstrated that a synthetic antioxidant, pyrrolidine dithiocarbamate (PDTC) can selectively downregulate HPV expression in human keratinocytes and cervical cancer cell lines. Since a redox regulatory pathway is involved in the expression of HPV that can be modulated by an antioxidant-induced reconstitution of the AP-1 transcription complex, we have used curcumin (diferuloylmethane), an active component of the perennial herb turmeric, which is a potent antioxidant and is well-known for its antiinflammatory and anticarcinogenic activity, to modulate the transcription of AP-1 and HPV. We demonstrate for the first time that curcumin can selectively downregulate HPV18 transcription as well as the AP-1 binding activity in HeLa cells. Most interestingly, curcumin can reverse the expression dynamics of c-fos and fra-1 in this tumorigenic cell line, mimicking the expression pattern observed in normal controls or precancerous lesions. Observation of curcumin-mediated complete downregulation of AP-1 binding activity and reversal of c-fos/fra-1 transcription to a normal state in tumorigenic HeLa cells represents a novel mechanism that can control transcription of pathogenic HPVs during keratinocyte differentiation and progression of cervical cancer. Our study thus provides a basis for developing a novel therapeutic approach to control pathogenic HPV infection by using potent antioxidative agents, such as curcumin.

Chlamydia trachomatis and human papillomavirus infection in Indian women with sexually transmitted diseases and cervical precancerous and cancerous lesions

OBJECTIVES

Sexually transmitted diseases (STDs) and anogenital cancers are the major health problems in Indian women but no reliable estimate of the prevalence of either genital chlamydial infection or human papillomavirus (HPV) infection in STD patients is available. The aim of this study was to detect the frequency of Chlamydia trachomatis and the most prevalent high-risk HPV type 16 (HPV 16) infection in Indian women, with STDs and precancerous and cancerous lesions of the uterine cervix by polymerase chain reaction (PCR), and their comparison with those of conventional serology and antigen tests used for C. trachomatis detection.

METHODS

Endocervical swabs or scrapes were collected from 50 women with STDs and 30 normal healthy women attending the STD clinics of Smt. Sucheta Kripalani Hospital, New Delhi. Scraped cervical cell specimens were also collected from 50 women with precancerous and cancerous lesions of the uterine cervix. Detection of C. trachomatis and HPV was carried out by PCR using chlamydia and HPV genome-specific oligonucleotide primers. The detection of chlamydial antigen and IgG-specific antibodies was carried out by enzyme immunoassay (EIA) and serological enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

A chlamydia plasmid-based PCR assay detected 50% (25 of 50) positivity of C. trachomatis in STD patients and HPV 16 DNA was found in 30% (15 of 50) of these cases which are significantly higher than those found in healthy controls. The PCR estimate of chlamydia was found to be higher than its reported frequency by tissue culture. The EIA could detect chlamydial antigen in only 13 cases (26%) while serological ELISA revealed evidence of chlamydia IgG-specific antibodies in 26 (52%) cases. Interestingly, in women with precancerous and cancerous lesions, the rate of HPV 16 infection was very high (52% and 72%, respectively), whereas the frequency of chlamydia infection was found to be 12-22% only. Occurrence of other sexually transmitted agents was also evaluated in the women.

CONCLUSIONS

This is the first PCR estimate of genital chlamydial (50%) and HPV 16 (30%) infection in STD patients and women with precancerous and cancerous lesions of the uterine cervix in India. The PCR method seems to be a good alternative to tissue culture.

DNA aneuploidy and infection of human papillomavirus type 16 in preneoplastic lesions of the uterine cervix: correlation with progression to malignancy

A microphotometric analysis of nuclear DNA ploidy and detection of human papillomavirus (HPV) type 16 DNA was carried out in 50 cases of mild, moderate and severe dysplasia of the uterine cervix along with an equal number of matched controls in order to understand their relative importance in malignant progression of the disease in women. Twenty-two (44.0%) cases of dysplasia showed an aneuploid DNA pattern while positivity for high risk HPV type 16 DNA was found in twenty-three (46.0%) cases. Thirty-four women with twice confirmed mild and moderate dysplasia have been followed up for 24 months. Follow-up data revealed that eight (72.7%) of the 11 patients having an aneuploid DNA pattern and positivity for HPV 16 progressed to carcinoma in situ (CIS) compared to only one (4.4%) case which was positive for HPV 16 with a non-aneuploid DNA pattern. This suggests that a combined analysis of infection of high risk HPV type 16 and aneuploid DNA pattern may serve as an important biological indicator to predict the potential of precancerous lesions of the uterine cervix for progression to malignancy.

Absence of human papillomavirus DNA in breast cancer as revealed by polymerase chain reaction

Oncogenic human papillomavirus (HPV) types 16 and 18 commonly associated with cervical cancer are found in many epithelial malignancies at extra-genital sites including breast. The transforming gene products of HPV have also been shown to immortalize breast epithelial cells in vitro. But the findings of HPV DNA in breast carcinoma are found to be contradictory. In the present study fine needle aspirate cell (FNAC) samples from 26 breast cancer patients and four breast tumour biopsies were analysed for the presence of HPV 16 and 18 DNA sequences by both polymerase chain reaction (PCR) and Southern blot hybridization. Of 26 fine needle aspirate cell samples and four breast cancer biopsies, not a single sample was found to be positive by either PCR or Southern blot hybridization. The observation of complete absence of HPV DNA sequences in breast cancer refute the possibility of any role for oncogenic genital HPV types 16 and 18 in the pathogenesis of breast cancer.

Human papillomavirus DNA sequences in adenocarcinoma of the uterine cervix in Indian women

BACKGROUND

Infection with human papillomavirus (HPV) is considered to be the principal causal agent in the development of squamous cell carcinoma of the uterine cervix. Although adenocarcinoma of the cervix originates adjacent to the squamous epithelial neoplastic lesions, the etiopathogenesis of adenocarcinoma is not yet clearly understood. Recent studies have raised more controversy, rather than answering the question of whether specific HPV infection also plays a role in the development of adenocarcinoma of the cervix. Molecular DNA hybridization techniques were used to detect HPV types prevalent in both adenocarcinoma and squamous cell carcinoma of the uterine cervix, which is the most common cancer in Indian women.

METHODS

Histologically confirmed, formaldehyde-fixed, paraffin-embedded tissue sections from 12 cases of adenocarcinoma and 30 cases of squamous cell carcinoma of the uterine cervix were analyzed retrospectively for the presence of HPV DNA types 6b, 11, 16, and 18 by both Southern blot hybridization and in situ hybridization.

RESULTS

Of 12 adenocarcinomas, 5 (41.67%) tumors were positive for HPV DNA: All five cases were positive for HPV 16, and two (16.6%) of these were hybridized again to the HPV 18-specific DNA probe. All tumors were negative for HPV 6b and 11. In addition, no biopsy specimens were positive after hybridization with a mixed probe of HPV 31, 33, 35, 39, and 45. These results were compared to those obtained for 30 squamous cell carcinomas of the cervix. Although 20 (66%) were exclusively positive for HPV 16 and 6 (20%), more tumors were of HPV 16 related types as detected under nonstringent conditions of hybridization, only one (3%) was positive for HPV 18. The results of in situ hybridization were found to be in good agreement with those of Southern blotting.

CONCLUSIONS

HPV 16 is the type present almost exclusively in squamous cell carcinoma of Indian women. A higher frequency of HPV 16 in adenocarcinoma of Indian women, in contrast to HPV 18, as reported from other regions, may be attributed to geographic variation rather than to histologic differences only, and both HPV 16 and 18 may be present in adenocarcinoma of the uterine cervix.

A high frequency of human papillomavirus DNA sequences in cervical carcinomas of Indian women as revealed by Southern blot hybridization and polymerase chain reaction

Ninety-six colposcopically directed biopsies from squamous epithelial carcinoma of the uterine cervix and 22 age-matched normal control biopsy specimens were examined by both Southern blot hybridization and polymerase chain reaction (PCR) for the presence of different human papillomavirus (HPV) DNA types. Cancer of the uterine cervix, which is the most common malignant disease in Indian women, showed a high frequency (98%) of HPV as compared to those reported from other parts of the world. HPV type 16 was found to be the dominant (64%) type while the frequency of HPV type 18 was very low (3%). On individual typing of HPV, no biopsy was found to contain any other known HPV types under stringent conditions of hybridization except a single case of HPV type 11. Only one case of double infection with HPV types 16 and 18 was recorded. Under low stringency conditions of hybridization with a mixed probe of HPV types 16 and 18, 29 additional biopsies were found to be positive. Southern blot hybridization alone detected HPV DNA in 92% of the cases but none in the controls. By PCR, six (6.25%) more cases and four (18.18%) healthy women were found to be positive for HPVs. Analysis of the physical state of HPV 16 indicated integration in about 70% of carcinoma cases while 30% of them were in episomal form. The findings suggest that infection with HPV is an important etiologic factor for the development of cervical cancer, that a number of such tumours may arise without HPV infection, and that integration of the viral DNA into host genome is not always essential for malignant progression.(ABSTRACT TRUNCATED AT 250 WORDS)

A simple and rapid method of high quantity DNA isolation from cervical scrapes for detection of human papillomavirus infection

Infection with human papillomavirus (HPV) is an important etiological factor in the development of cervical cancer, and detection of the viral genome is of prognostic importance, particularly for preneoplastic lesions. We developed a simple, easy and efficient non-organic method of DNA extraction from cervical scrapes for reliable detection of HPV DNA sequences. The method involves incubation of cell nuclei in higher concentration of proteinase K at 65 degrees C for 2.5 h. Following prolonged incubation at higher temperature, the enzyme is autoinactivated and the DNA isolated can be used directly for analysis without further purification. The recovery of DNA is more than 95% and it can be easily cleaved by restriction enzymes and is suitable for amplification by the polymerase chain reaction (PCR). The whole procedure is carried out in a single Eppendorf tube and a large number of specimens can be processed at a time without any error of handling. DNA extracted from a single smear sample is sufficient to conduct as many as four different molecular biology tests. This provides an opportunity for verification of sensitivity, specificity and reliability of each test for diagnosis of HPV infection without resorting to biopsy.