SUBEXPRESSÃO DOS GENES RB, P53 E MYC MEDIADA POR HPV E SUPEREXPRESSÃO DE GENES ENVOLVIDOS NO PROCESSO INFLAMATÓRIO COX2, PGE2 E EGFR COM IMPORTÂNCIA TERAPÊUTICA EM CÂNCER PENIANO.

Abstract

Penile cancer (PeCa) is a rare neoplasm with higher incidence in regions with low socioeconomic indexes. In Brazil, most of the men afflicted by this disease reside in the North and Northeast. Among the main risk factors are lack of hygiene, phimosis, high-risk human papillomavirus (HPV) infection and chronic inflammation. Although the role of inflammation and HPV infection is known in some cancers, the relationship between these two factors and the disruption of genes involved in the CaPe genesis is not yet well established. Thus, our main goal was to determine the expression of genes involved in the process of chronic inflammation and in the carcinogenesis mediated by HPV infection and the role of the deregulation of these genes in the establishment and progression of penile tumor. For this purpose, fresh and formalin-fixed paraffin-embedded (FFPE) tissues from 55 patients with penile cancer were evaluated. HPV detection and genotyping were carried out by nested PCR and direct sequencing in all samples. A subgroup (N = 37) was evaluated by qRT-PCR to determine COX-2, EGFR, MYC, RB and P53 gene expression. For this, sections of FFPE tissues containing more than 70% tumor cells were analyzed. Protein expression of these genes and PGE2 were determined by immunohistochemistry in the same tumor tissues. An analysis of the association between the clinical-histopathological parameters, presence of HPV, and gene and protein expression was performed. All tumors were classified as epidermoid squamous cell carcinoma. HPV DNA was detected in 80% of tumors, of which 95% had at least one high-risk subtype, and HPV16 was the most frequent subtype (63%). Among the HPV negative samples in the tumor tissue, 14% were positive in the tissue adjacent to the tumor, so that 94% of the patients, in total, were positive for the presence of HPV DNA.. Overexpression was identified in all genes involved in the inflammatory process. EGFR showed overexpression in 84% of the samples, while COX2 and PGE were overexpressed in 40% of the tumors, each. There was an associationbetween the levels of EGFR and COX2 expression, and between COX2 and PGE2. On the other hand, the genes related to HPV infection, MYC, RB and P53, were underexpressed in 97%, 85% and 81% of the samples, respectively. The gene expressions did not show any association with clinical-histopathological variables. This study describes the repression of RB and P53 activity in HPV + tumors, suggesting that there is a mechanism of control of these genes, possibly mediated by the virus. The high detection of HPV infection shows the importance of the immunization of boys in the prevention of penile cancer. Our data emphasize the need to expand the vaccine coverage to cover types of HPV present in penile cancer. The overexpression of EGFR / COX2 / PGE2, and the association found between them, support the possibility of therapeutic use of anti-EGFR and anti-COX drugs in penile tumors.