RESUMO
Background: Proteins encoded by FAS, BCL-2 and TP53 genes are major regulators of cellular survival and apoptosis. Results of recent investigations show remarkable biological features of these factors, which propose their role in the course of cancer. Therefore, it is plausible to test whether transcripts of these genes could be detected in the peripheral blood cells of patients with breast cancer. Materials and Methods: Real-time polymerase chain reaction assay was performed to detect FAS, BCL-2, and TP53 gene transcripts in the peripheral blood samples of 50 women with histologically confirmed infiltrative ductal carcinoma of the breast. Gene expression of patients was compared with 40 healthy women without history of malignancies or autoimmune disorders. Results: The relative overexpression of BCL-2 in the blood cells from patients of early stages (I and II), nonmetastatic and low-grade tumors compared with healthy individuals, was shown by measuring the gene transcript. Similarly, 3-4-fold higher expression of FAS was found in those patients. The measurement of TP53 transcripts also showed higher levels of gene expression in patients compared with healthy controls. BCL-2 gene expression showed a significant correlation with FAS, while such a correlation was not observed between BCL-2 and TP53 . Conclusion: It seems tumor cells overexpress BCL-2 to inhibit apoptosis and guarantee their cell survival. As a physiologic response, FAS and TP53 could be upregulated to suppress tumors. However, these pathways at early stages of disease may be inadequate and cause progressive malignancy.