Detecção de papilomavírus humano em amostras de mama de mulheres atendidas em serviço de referência em mastologia no Ceará

Abstract

Breast cancer is the second most common malignant neoplasm among Brazilians, representing the highest mortality rate amongst cancers. It has multifactorial aetiology and known risk factors, as well as unknown causes. Some viruses, such as HPV, may be related with the occurrence of this neoplasm. Over 200 types of HPV are classified according to their oncogenic potential. The virus is highly contagious for it may be transmitted by direct contact with infected skin or mucosa, being also sexually transmitted. Because it has well elucidated oncogenic mechanisms and be the responsible for almost all cervical cancer cases worldwide, the HPV has been studied for its role on breast cancer pathogenesis. Some methods of diagnosis for detection and preventions of this kind of cancer, such as oncotic cytology, are not specified for this virus, incurring the infection by HPV on the cytopathic pattern. Polymerase chain reaction, however, is an efficient method for detection of this virus which amplifies the viral DNA. The objective of this current article is to determine the HPV positivity in mammary samples and understand its frequency related to the type of sample and the age of the patients. For this matter, viral DNA from several samples was extracted and purified for further amplification of the intergenic regions E6-E7 by nested PCR technique and genotyping of 11 different kinds of HPV (16, 18, 31, 45, 59, 6/11, 33, 52, 56 and 58). The positivity rate found for HPV infections was 20.3%, being that 7.6% from biopsy samples and 12.7% from ductal samples. The genotyping founds were composed by HPVs 6/11, 16 and 33, in which 6/11 presented the highest frequency. Only 12.5% of the patients who presented positive diagnosis for HPV infection were carriers of breast cancer, in which 3.1% of the patients were younger than 42 years old and 9.4% were between 42 and 51 years old. This study indicates the utility of our PCR protocol for HPV’s detection on mammary samples and HPVs’ typing. When comparing our results with other studies there are differences between the frequency and the genotypes groups of detected HPVs. Those differences may be justified by the type of analysed sample, HPV detection method and geographic differences. The analysis relating the virus with the demographic variable could have been more satisfactory with the presence of complete demographic data.