Down-regulation of p16 and MGMT promotes the anti-proliferative and pro-apoptotic effects of 5-Aza-dC and radiation on cervical cancer cells.

Cervical cancer is one of the most common malignancies of the female reproductive system. Therefore, it is critical to investigate the molecular mechanisms involved in the development and progression of cervical cancer. In this study, we stimulated cervical cancer cells with 5-aza-2'-deoxycytidine (5-Aza-dC) and found that this treatment inhibited cell proliferation and induced apoptosis; additionally, methylation of p16 and O-6-methylguanine-DNA methyltransferase (MGMT) was reversed, although their expression was suppressed. 5-Aza-dC inhibited E6 and E7 expression and up-regulated p53, p21, and Rb expression. Cells transfected with siRNAs targeting p16 and MGMT as well as cells stimulated with 5-Aza-dC were arrested in S phase, and the expression of p53, p21, and Rb was up-regulated more significantly. However, when cells were stimulated with 5-Aza-dC after transfection with siRNAs targeting p16 and MGMT, proliferation decreased significantly, and the percentage of cells in the sub-G1 peak and in S phase was significantly increased, suggesting a marked increase in apoptosis. But E6 and E7 overexpression could rescue the observed effects in proliferation. Furthermore, X-ray radiation caused cells to arrest in G2/M phase, but cells transfected with p16- and MGMT-targeted siRNAs followed by X-ray radiation exhibited a significant decrease in proliferation and were shifted toward the sub-G1 peak, also indicating enhanced apoptosis. In addition, the effects of 5-Aza-dC and X-ray radiation were most pronounced when MGMT expression was down-regulated. Therefore, down-regulation of p16 and MGMT expression enhances the anti-proliferative effects of 5-Aza-dC and X-ray radiation. This discovery may provide novel ideas for the treatment of cervical cancer.

Three-step versus "see-and-treat" approach in women with high-grade squamous intraepithelial lesions in a low-resource country.

OBJECTIVE: To investigate the frequency of cervical intraepithelial neoplasia (CIN) 2 or greater in women with high-grade squamous intraepithelial lesion (HSIL), and to evaluate whether colposcopically-directed biopsy is a necessary procedure for managing HSIL in a low-resource country. METHODS: A retrospective review was undertaken of women with HSIL on a Pap smear. RESULTS: Of 348 women who had undergone colposcopically-directed biopsies and loop electrosurgical excisional procedure (LEEP), 321 (92.2%) had CIN 2 or greater. Of these, 279 were diagnosed with CIN 2 or greater on biopsy as were 264 on LEEP. The lesions in women who had CIN 2, satisfactory colposcopy, and more biopsies were more likely to be completely excised by biopsy. The mean length of time between the initial Pap smear and LEEP was significantly longer than between the initial Pap smear and biopsy. CONCLUSION: Women with HSIL can be effectively managed using the see-and-treat approach in a low-resource country owing to the frequency of CIN 2 or greater.

[Study on cervical intraepithelial neoplasia in relation to human papillomavirus and co-factors: a case-control study in China and Australia].

OBJECTIVE: This study was to elucidate the role of human papillomavirus (HPV) types and cofactors in the development of cervical intraepithelial neoplasia (CIN). METHODS: Two hundred and twelve women with CIN and 427 women with normal cervical cytology (control group) were recruited from China and Australia. A questionnaire was administered to each participant to obtain the demographic and risk factor information. Cervical biopsies or smears were taken to detect HPV DNA by PCR and to identify HPV types by direct sequencing and/or Amplicor hybridisation. Data were analyzed by logistic regression. RESULTS: HPV prevalence rates of specimens from Chinese and Australian were 11% and 15% among controls (P >0.05), with 99% and 85% of CINs (P<0.001), respectively. The presence of any type of HPV DNA was strongly associated with CIN with OR 43.3 for Chinese and OR 541.6 for Australian women. The strongest risk was for HPV16,followed by HPV31 in Australians, but HPV58, 59 in Chinese women. The risk for multiple HPV infection was stronger in the Australians than that in the Chinese cohort. Except for HPV infection, educational attainment was unexpectedly associated with an increased risk for CIN in Chinese, and cancer history in family was a risk factor for Australians. For the combined cohorts, educational attainment, and frequency of vitamin consumption were identified to be risk factors for CIN. CONCLUSION: Cervical HPV DNA was a major risk factor, with the highest relative risk for type 16 HPV infection for CIN. There were variations in the distribution of HPV genotypes and cofactors in China versus Australia and in CIN.

[Combining high-risk human papillomavirus DNA test and cytological test to detect early cervical dysplasia].

OBJECTIVE: To assess the value of combining high-risk human papillomavirus (HPV) DNA test and cytological test in detection of early cervical dysplasia. METHODS: During January 2003 to June 2004, a total of 5210 women were screened by combining high-risk HPV DNA test (hybrid capture II, HC-II) and cytological test (liquid-based ThinPrep cytology test), and the abnormal cytological or HPV DNA findings were further biopsied under the colposcope. RESULTS: The age of the patients was between 17 to 80, the average was 34 +/- 9. Final pathological diagnosis was HPV infection in 890 cases, cervical intraepithelial neoplasia (CIN) I in 83 cases, CIN II in 73 cases, CIN III in 80 cases, invasive cervical cancer in 54 cases, endometrial cancer in 5 cases, vaginal intraepithelial neoplasia in 1 case and cervical tuberculosis in 1 case. Based on the criteria of histology and pathology, the sensitivity, specificity, positive-predictive value and negative-predictive value of high-risk HPV DNA test for detecting all cases of CIN II, III were 92.22%, 74.71%, 5.19% and 99.84% respectively. In detecting all cases of CIN II, III by cytological test, for atypical squamous cell of undetermined signification (ASCUS), the sensitivity, specificity, positive-predictive value and negative-predictive value were 90.00%, 80.34%, 11.94% and 99.63% respectively; for low-grade squamous intraepithelial lesion (LSIL), the sensitivity, specificity, positive-predictive value and negative-predictive value were 70.13%, 91.58%, 11.11% and 99.51% respectively; for high-grade squamous intraepithelial lesion (HSIL), the sensitivity, specificity, positive-predictive value and negative-predictive value were 48.05%, 98.46%, 31.90% and 99.21% respectively. By the combination of high-risk HPV DNA test and cytological test, the sensitivity, specificity, positive-predictive value and negative-predictive value for detecting all cases of CIN II, III were 98.70%, 73.08%, 5.21% and 100.00% respectively. The infection rate of HPV in cervical cancer was 85.2% (46/54), in CIN III 92.5% (74/80), in CIN II 86.3% (63/73) and in CIN I 45.8% (38/83). CONCLUSIONS: High-risk HPV DNA test has high sensitivity and negative-predictive value. The combination of high-risk HPV DNA test and cytological test increases the sensitivity and negative-predictive value, but it does not increase the specificity. The performance of biopsy under the colposcope can help the diagnosis of cervical dysplasia.

[Pregnancy and delivery outcomes after loop electrosurgical excision procedure of cervical intraepithelial neoplasia].

OBJECTIVE: To investigate the effects of loop electrosurgical excision procedure (LEEP) on pregnancy and delivery outcomes of patients with cervical epithelial neoplasia (CIN). METHOD: The delivery data of 27 pregnant women who had LEEP from May 1995 to April 2002 were retrospectively collected and analysed. RESULTS: The mean age of the 27 women was 30.3 years (range 23 approximately 40 years). Ten women underwent artificial abortion. One ectopic pregnancy and two spontaneous miscarriages occurred at 6 to 8 weeks of gestation. There were 14 term pregnancies, 9 of them via vaginal delivery and 5 via caesarean section. The birth weight of newborns ranged from 2905 to 4000 g. All of newborns had a high Apgar score. No asphyxia occurred. CONCLUSIONS: LEEP is a safe and effective treatment for patients with CIN. It will not increase the risk of pregnancy and delivery of the patients.