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Background: The incidence of oral cancers associated with human papillomavirus (HPV) has been increasing in recent years. Therefore, it is necessary to elucidate HPV prevalence in oral cells and exposure to risk factors in various age groups.Methods: Oral rinse samples from healthy individuals in northern Thailand were investigated for HPV prevalence and genotyped using the polymerase chain reaction (GP5+/6+ primers) and DNA sequencing of the PCR products.Results: Samples were collected from 594 participants between 4 and 60 years of age. HPV was detected in 3.7% of samples. The prevalence of HPV-positive cases was 8.6% in the 31-50 age group. HPV prevalence increased with age and was the highest (9.2%) in the 41-50 age group, but decreased (to 3%) in the 51-60 age group. Risk factors significantly associated with HPV-positive cases included alcohol consumption, coffee drinking, sexual activity, and having children. HPV 16 and 18 were common genotypes, especially in the 31-50 age group, and were associated with having sexual activity (odds ratio 19.0 [95% CI: 2.5-142.5]). At follow-up of some individuals in the 4-10 age group, a 9-year-old child was found to be positive for HPV18.Conclusions: These results suggest that HPV can be acquired at a young age and the prevalence peaks in the middle age class among healthy individuals in northern Thailand, especially in the 31-50 age group. [ABSTRACT FROM AUTHOR]

Human papillomavirus (HPV) is an independent risk factor for development of oral squamous cell carcinoma (OSCC). This study aimed to investigate the role of HPV infection and the trend in percentage of HPV-associated OSCC over a 5-year period in northeastern Thailand. In this case-control study, 91 exfoliated oral cell samples and 80 lesion cell samples from OSCC cases and exfoliated oral cells from 100 age/gender-matched controls were collected. HPV infection was investigated by PCR using GP5+/GP6+ primers followed by HPV genotyping using reverse line blot hybridization. Quantitative RT-PCR was used to evaluate HPV oncogene transcription. Temporal trends of HPV infection were evaluated in archived formalin-fixed paraffin-embedded (FFPE) OSCC tissues using in situ hybridization. HPV DNA was found in 17.5% (14/80) of lesion samples from OSCC cases and 29.7% (27/91) of exfoliated oral cell samples from the same cases. These values were significantly higher than in exfoliated oral cell samples from controls (13%, 13/100). HPV-16 was the genotype most frequently found in OSCC cases (92.8%, 13/14 infected cases). Interestingly, HPV oncogene mRNA expression was detected and correlated with OSCC cases ( P < 0.005). Of 146 archived FFPE OSCC samples, 82 (56.2%) were positive for high-risk HPV DNA and 64 (43.8%) cases were positive for HPV E6/E7 mRNA expression. There was a trend of increasing percentage of HPV-associated OSCC from 2005 to 2010. This was especially so for females with well-differentiated tumors in specific tongue sub-sites. We suggest that HPV infection plays an important role in oral carcinogenesis in northeastern Thailand. [ABSTRACT FROM AUTHOR]

Background Besides the well-known risk factors, Epstein-Barr virus ( EBV) might play a significant role in oral squamous cell carcinoma ( OSCC). To explore the role of EBV in OSCC, the prevalence of EBV infection in oral exfoliated cells of OSCC cases and controls in northeastern Thailand was investigated, and the association of EBV in tumor lesion cells was further confirmed. Methods Oral exfoliated cells were collected from OSCC cases and non-cancer controls. Cells from tumor lesions were taken from OSCC patients for further strong confirmation of the association of EBV with OSCC. EBV DNA was detected by polymerase chain reaction ( PCR) using primers specific for EBV DNA polymerase. The EBV DNA positive samples were confirmed further by nested PCR. Results Epstein-Barr virus was detected in the oral exfoliated cells of 45.05% of OSCC patients and 18.08% of the non-cancer control ( P < 0.001). Similarly, EBV was detected in 32.5% of the tumor lesions. Betel quid chewing was statistically significantly associated with EBV prevalence ( OR = 2.08), whereas no association with tobacco smoking and alcohol consumption. Alcohol consumption and betel quid chewing were significantly associated with OSCC ( OR = 3.05 and OR = 5.05, respectively), but tobacco smoking was not associated. Interestingly, EBV was significantly associated with OSCC ( OR = 3.76). Conclusions Epstein-Barr virus prevalence is associated with OSCC and seems to be enhanced by betel quid chewing, suggesting that EBV may, together with betel quid chewing, act as an important etiological risk factor of OSCC. [ABSTRACT FROM AUTHOR]

To understand the potential role in cervical cancer development of the three most common high-risk human papillomavirus (HRHPVs) in Thai women, HPV genotypes and viral genome statuses in different cervical lesions were investigated. Cervical tissues consisting of no cervical intraepithelial neoplasia (84 cases), grade I cervical intraepithelial neoplasia (176 cases), grade II-III cervical intraepithelial neoplasia (91 cases), and squamous cell carcinoma (66 cases) were subjected for HPV genotyping by polymerase chain reaction (PCR) and reverse line blot hybridization assay and for HPV genome status determination by amplification of papillomavirus oncogene transcripts (APOT) assay. HPV prevalence was 28.6% in no cervical intraepithelial neoplasia, 40.3% in grade I cervical intraepithelial neoplasia, 70.3% in grade II-III cervical intraepithelial neoplasia and 86.4% in squamous cell carcinoma cases. The three most common HR-HPV types were HPV 16, 58, and 18 which were distributed in all cervical lesions. HPV physical statuses could be investigated in 4 no cervical intraepithelial neoplasias, 2 grade I cervical intraepithelial neoplasias, 28 grade II-III cervical intraepithelial neoplasias and 31 squamous cell carcinomas. The integrated-derived transcripts were found 3.6% in grade II-III cervical intraepithelial neoplasia and 48.4% in squamous cell carcinoma, whereas no viral genome integration was found in the group of no cervical intraepithelial neoplasia or grade I cervical intraepithelial neoplasia samples. The frequencies of HR-HPV integration in squamous cell carcinoma were found 40%, 100%, 20% of HPV 16, 18, and 58. This study indicates the oncogenic potential ability of the three most common HR-HPVs associated with cervical cancer progression [ABSTRACT FROM AUTHOR]

Enhanced expression of the HPV 16 E6-E7 oncogenes may trigger neoplastic transformation of the squamous epithelial cells at the uterine cervix. The HPV E2 protein is a key transcriptional regulator of the E6-E7 genes. It binds to four E2 binding sites (E2BSs 1-4) in the viral upstream regulatory region (URR). Modification of E2 functions, for example, by methylation of E2BSs is hypothesized to trigger enhanced expression of the viral E6-E7 oncogenes. In the majority of HPV-transformed premalignant lesions and about half of cervical carcinomas HPV genomes persist in an extra-chromosomal, episomal state, whereas they are integrated into host cells chromosomes in the remaining lesions. Here we compared the methylation profile of E2BSs 1-4 of the HPV 16 URR in a series of 18 HPV16-positive premalignant lesions and 33 invasive cervical cancers. CpGs within the E2BSs 1, 3, and 4 were higher methylated in all lesions with only episomal HPV16 genomes compared with lesions displaying single integrated copies. Samples with multiple HPV16 integrated copies displayed high methylation levels for all CpGs suggesting that the majority of multiple copies were silenced by extensive methylation. These data support the hypothesis that differential methylation of the E2BSs 1, 3 and 4 is related to the activation of viral oncogene expression in cervical lesions as long as the viral genome remains in the episomal state. Once the virus becomes integrated into host cell chromosomes these methylation patterns may be substantially altered due to complex epigenetic changes of integrated HPV genomes. [ABSTRACT FROM AUTHOR]

Aim: This study investigated the utility of visual inspection with acetic acid (VIA) as a method for cervical cancer screening in Thailand and examined the relationship of VIA to high-risk human papillomavirus (HR-HPV) status. Methods: Cervical cells were collected from 160 patients receiving a Pap smear. VIA was performed on the cervix of the patients by application of 5% acetic acid. HPV screening of DNA extracted from cytology samples was performed by PCR using the GP5+/6+ primer system followed by reverse line blot hybridization genotyping. Results: The majority (96.9%) of the patients were diagnosed with normal or inflammatory cytologic changes. 32.8% of normal cytology and 42.0% of inflammation cases showed positive acetowhite staining. 3.1%, 38.1% and 42.5% of subjects were positive for an abnormal Pap test, VIA test, and HPV DNA, respectively. VIA demonstrated 50% sensitivity and 66.7% specificity for abnormal histology with PPV and NPV values of 50% and 66.7%, respectively, whereas HPV DNA test showed 100% sensitivity. HPV16 was the most common (54.4%) and HR-HPV was detected in 36.3% of all cases. 48.5% of HR-HPV positive and 36.8% of HR-HPV negative cervices stained with acetowhite following the VIA test. Conclusion: The VIA test is a simple method for cervical cancer screening; however, a significant proportion of patients with normal or inflammatory cytology were positive by this test. Further, HR-HPV in women without acetowhite staining was demonstrated. Therefore, some form of HR-HPV detection test may be required for combination with cervical cell screening even in low-resource nations. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To compare the clearance rate of HPV infection among women aged older than 30years with biopsy-confirmed cervical low-grade squamous intraepithelial lesions (LSIL) 1year after cryotherapy with the spontaneous clearance rate (observation). Method: HPV DNA typing by polymerase chain reaction and reverse line blot hybridization were used to identify 14 high-risk types and 23 low-risk types. HPV DNA sequencing was also used for other types. Result: Between December 2007 and March 2009, 100 women were recruited to the study and 60 cases had positive results on HPV testing. Twenty-nine patients were randomly allocated to the cryotherapy group and 31 to the observation group. At 1year, 89.7% (26/29; 95% CI, 78.6–100%) of the cryotherapy group and 90.3% (28/31; 95% CI, 79.9–100%) of the observation group had negative results on HPV testing (0.6% difference; 95% CI, –15.8 to 14.6%, P =0.94). Conclusion: Cryotherapy failed to increase the clearance of prevalent HPV infections among women with LSIL, although in both arms the clearance rates were above 80%. However, in coupling with visual inspection with acetic acid as a single visit approach, its effect on prevention of HSIL and cervical cancer is still promising. Therefore, cryotherapy should not be withdrawn from such programs. (ClinicalTrials.gov Identifier: NCT00566579). [Copyright &y& Elsevier]

Aim: To determine the prevalence of Chlamydia trachomatis infection and to evaluate the relation of previous and persistent chlamydial infection to ectopic pregnancy (EP) among women in Khon Kaen, Thailand. Methods: We enrolled 32 EP patients in the case group. Control subjects were 57 women undergoing tubal ligation after normal labor. Serum immunoglobulin (Ig)G and IgA antibodies to C. trachomatis were determined using ELISA. Chlamydial DNA was investigated using polymerase chain reaction. Results: The prevalence of chlamydial DNA in fallopian tube tissue was 34.38% of EP patients whereas none was detected in controls. In cervical cells, however, no significant difference in chlamydial DNA between cases (3.13%) and controls (3.51%) was detected. Serum-specific IgG was found more in the EP group than in the control group (21.88% and 5.26%, respectively; P < 0.05). Serum-specific IgA was detected in 5.26% of the control women but not in the EP group. Analysis by multivariate conditional logistic regression revealed a significant association between EP and the various risk factors. Among these, abortion, previous EP and age at first intercourse <15 years were strong predictors of EP. However, the association between specific IgG and EP became non-significant in this analysis. Conclusions: No strong independent association was shown between chlamydial antibodies and the EP risk in Thai women despite DNA detection in fallopian tube tissue. In contrast, factors including abortion, previous EP, and age at first intercourse <15 years were the significant predictors of EP. Efforts to address these other variables will help more in reducing the EP burden in Thai women compared to eliminating C. trachomatis. [ABSTRACT FROM AUTHOR]