Identification of circulating tumor cells in anal canal cancer in their interaction with the HIV virus and HPV

Abstract

Cancer has become a major public health problem in developed and developing countries, accounting for more than six million cases of deaths each year, accounting for about 12% of all causes of death in the world. Anal cancer accounts for 4% of all malignant neoplasms of the lower digestive tract and has one of the etiologic factors, the human papillomavirus (HPV), which gives it a strong association with sexually transmitted diseases. HIV-induced immunosuppression may also accelerate the progression of HPV-associated precursor lesions. It is believed that the spread of cancer requires the presence of circulating tumor cells (CTCs) that come from the primary tumor or metastatic site. Many studies have shown that CTCs are good markers for evaluating tumor evolution. In addition, these cells are useful in monitoring response to treatment, contributing to advances in personalized medicine. The present study has as main objectives: 1) To detect circulating tumor cells in patients with cancer of localized anal canal and to identify by molecular biology the presence of HPV virus in these cells; 2) Validate the detection of CTCs in anal canal cancer; 3) Validate the detection of CTCs in anal canal cancer; 4) To study the relation of the HPV virus in the CTCs of cancer of anal canal; 5) Evaluate if there is a correlation between the HIV load, the presence of HPV and the amount of CTCs, and correlate the findings with the clinical evolution of the patients. It will require 30 whole blood samples from patients with localized anal cancer and candidates for definitive treatment with chemo radiotherapy. Patients will have approximately10 ml of blood collected in EDTA tubes at two different times: before the start of chemotherapy and after the end of treatment. The collected blood will be filtered on a membrane by the ISET (Isolation by Size of Epithelial Tumors Cells) apparatus. At the moment of the analysis, 4 spots will be cut for counting and characterization of the CTCs, after which DNA and RNA extraction will be performed on the CTCs. We will use the Quiagen Universal kit, followed by the polymerase chain reaction (PCR) using MY09 / MY11 primers amplifying 450 bp fragments. A descriptive analysis of all clinicopathological variables, as well asthe count of CTCs and the presence of HPV within them will be made. We hopethis study will verify whether CTCs may be infected with HPV in patients with analcanal cancer if the presence of the virus in CTCs determines worse or better outcome and if there is interaction with HIV. With the results, we can propose new diagnostic tools. (AU)