Detection of human papillomavirus, viral load and risk factors in patients with precancerous diseases and malignant neoplasms in St. Petersburg

Abstract

Molecular genetic studies have revealed the involvement of different genotypes of human papillomavirus (HPV) in the carcinogenesis of cervical cancer and malignant lesions of other localizations. It is reported that patients with HPV-positive cancer have a better prognosis of the disease and survival than patients with unconfirmed HPV infection or with a low viral load. The objective was to identify the detectability, viral load, genotypes of human papillomavirus in HPV-associated precancerous and malignant neoplasia of various localization and to determine risk factors for their occurrence in the metropolis of St. Petersburg at the present time.
 Materials and methods. A total of 80 samples taken from morphologically confirmed tissues of oropharyngeal and anal cancer, malignant tumors of vulva, vagina, cervix and cervical intraepithelial neoplasia were studied in St. Petersburg Clinical Oncologic Center. Detection, quantification and genotyping of HPV DNA were carried out by real-time PCR at the St. Petersburg Pasteur Institute.
 Results. HPV was detected in 89.7% (61/68) of patients with malignant tumors and 83.3% (10/12) with severe cervical dysplasia. The vast majority (85.9%) of HPV-positive patients were infected with HPV genotype 16; papillomavirus mixed infection (genotypes 16, 18, 31, 33, 35, 39, 45) was detected in anal cancer, cancer and severe cervical dysplasia. The average viral load in stages IIIIV of anal cancer, cervical cancer and severe cervical dysplasia exceeded 5.7 lg HPV DNA/105 cells. Among patients with oropharyngeal cancer, men predominated (85.7%); anal cancer was detected in women (90.0%). No statistically significant risk factors (smoking and alcohol consumption) for the occurrence of HPV-associated malignancies were identified.
 Conclusions. The detection of HPV, mainly of genotype 16, varied depending on the location of the neoplasia: anal cancer 100%, cancer of the female genitalia 94% (in case of cancer of the vagina and cervix 100.0%), head and neck cancer 76.2%. The highest HPV DNA load in the tumor tissue was found in IIIIV stages of the cervical and anal cancer.