Estudo do papilomavírus humano (HPV) 18 e variantes associadas ao câncer do colo do útero em usuárias da rede SUS, São Luís - Ma

Abstract

Introduction: Cervical cancer is the fourth most common type of cancer affecting women worldwide, with more than 80% of cases occurring in developing countries. Approximately 70 to 80% of this cancer is associated with Human Papillomavirus (HPV 16 and 18). Several studies report the intra-type diversity of HPV associated with the progression of infection to invasive cancer and may interfere biologically and etiologically in the development of cervical cancer. Among viral types, HPV 18 shows high oncogenicity and is the second most prevalent type in cervical tumors. Objective: The goal of this study was to analyze the intra-type variants of HPV 18 in samples of cervical cancer in women assisted in São Luís - MA. Method: Sociodemographic data were obtained through questionnaires applied to the patients. Tumor fragments from the cervix were collected and submitted to DNA extraction, and later Polymerase Chain Reactions (PCR) were performed to detect HPV. The Nested PCR technique was performed using primers PGMY09/11 for the first round and GP + 5/6 for the second round. Positive samples were submitted to an automated sequencing technique for viral genotyping. To characterize the HPV 18 strains, positive samples were submitted to PCR using specific primers for amplification of the HPV 18 virus LCR and E6 regions. Results: Data from 120 patients with cervical cancer were analyzed. Most of the women were between 40 and 49 years of age (34 / 28.33%), had primary schooling (51 / 42.50%), family income between 1 and 2 minimum wages (66/55%) and were married/consensual union (62 / 51.67%). There was no statistically significant association between HPV and socio-demographic variables and risk factors for cervical cancer (p <0.05). HPV was present in 88 women (73.33%). The most prevalent types were HPV 16 (48 / 54.0%), HPV 18 (12 / 13.8%), HPV 35 (6 / 6.9%) and HPV 45 (5 / 5.7%). Among the 12 samples positive for HPV 18, in 10 the variant A was identified (80%) and in 2 the variant B was identified (20%). The most prevalent histological type in HPV 18 tumors was epidermoid carcinoma in 6 samples (50.0%), followed by adenocarcinoma in 3 samples (25%). Conclusion: Knowledge of HPV 18 variants will provide a reference for the phylogenetic classification of biologically and epidemiologically relevant underlines in cervical cancer in the state of Maranhão.