The Prevalence of Human Papillomavirus in Cervical Cancer in Iran.

Background: The human papiloma virus (HPV), which is sexually transmitted, and most commonly causes genital warts, has been linked to cervical intraepithelial neoplasia and invasive carcinoma. Of ninety plus types of HPV, HPV-16 is the most prevalent in cervical cancer, followed by HPV-18, and HPV-33. As HPV's implication has not been assessed in the Middle East the main focus of this retrospective study was to determine the prevalence of HPV -16,18, and 33 in cases of cervical cancer from Iran. Material and Methods: This retrospective study covered 100 patients with uterine cervical carcinomas who were referred to two referral centers for cancer in Tehran-Iran. Pathological blocks were collected for these cases and initial review of the blocks showed poor specimens in 18 cases, which left 82 cases for the study. These samples were histologically examined to verify the presence and the type of carcinoma. The next step was in situ hybridzation for the detection of HPV common DNA. In Situ hybridization was preformed on all samples. Finally, Polymerase Chain Reaction (PCR) was preformed for the HPV types 16, 18, and 33. PCR amplification of exon 5 of the p53 gene was used as an internal control for the integrity of DNA. Takara PCR Human papilloma Detection method was used which includes primer for HPV 16, 18, and 33. Three primers were used alone, or in combination, in order to increase the sensitivity of the detection. Results: The majority of tumors were squamous cell carcinomas (87%). The rest were adenosquamous carcinoma and adenocarcinomas. None of the 82 different cervical carcinoma tissue samples were found to be positive by in situ hybridization. In the PCR samples, amplification of DNA was observed for 69 tumor specimens. In the remainning13 cases, the DNA in fixed tissue was degraded, as verified by the absence of an internal control band (p53). Out of the total 69 tumors (85.5%) with adequate DNA contained HPV band on PCR. The majority (73.9%) of HPV positive tumors contained HPV-16; the rest (11.6%) demonstrated type 18 and 33. There was no correlation between the histology of carcinoma and presence of types of HPV. Conclusion: The prevalence of HPV in carcinomas of uterine cervix in Iran is similar to those reported in other regions of the world. Similarly, it appears that HPV-16 is the most common type associated with cervical cancer in Iran. Further studies on larger samples of patients, particularly in those with pre-invasive forms of the disease, are needed to elucidate the carcinogenic role of HPV types in cervical cancer in Iranian women.