Quantificação de fragmentos de DNA livre no sangue periférico de portadores de câncer colorretal

Abstract

The colorectal cancer (CRC) is the third most common malignancy in the world and in Brazil, the fifth most diagnosed and the third cause of cancer deaths. The detection of molecular markers in peripheral blood applies to the early diagnosis of cancer, before and after surgery, reducing the time of identification of CCR and improving the treatment, it is less invasive and reducing costs. This work is quantified by Real Time PCR in absolute and direct, free of DNA fragments found in the serum of patients with colorectal cancer, thereby determining values that characterize the condition of carrier of tumor. For this, a method was developed in which the measurement used as reference samples of the actual fragments ALU115 and ALU247 purified and quantified. We studied 3 major groups: Control, with healthy volunteers; surgery, patients who have already been submitted to surgical removal of colorectal tumor and non-surgery, patients who have not removed the tumor through surgery. Observing the results we note that the groups differ mainly by the values of quantification ALU247. For the control group, the limits were between 91 fentogramas and 1.55 picograms. The non operated group had amounts ranging from 8.02pg to 23.54pg and the group operators, 80fg to 5.95pg. In contrary, the results presented by quantification ALU115 did not set limits defined capable of differentiating at least one of the groups. The control group presented as limits 2pg and 69.45pg and the non operated group, 9.71pg and and 381.56pg, the group operated, 10.69pg and 196.85pg. The non operated group showed a mean significant when compared to the other two groups, but showed minor differences in the quantification ALU247 (14.62 ± 4.73 pg - p <0.05). It could be concluded that direct measurement, using reference concentrations of the fragments themselves ALU115 and ALU247 is a simple methodology, low cost and with reliable results. Moreover, the quantification ALU247 is able to identify the condition of carrier of tumor.