Quantitative real time PCR analysis of apoptotic gene expression in chronic lymphocytic leukemia patients and their relationships with chemosensitivity

ABSTRACT

Background: Apoptosis-related gene expression such as BCL2, and p53 has been suggested in predicting the patient response to chemo- or radiotherapy, as well as patient's survival. Methods: The aim of this study was to determine changes in BCL2 and p53 apoptosis related gene expressions in chronic lymphocytic leukemia (CLL) patients in response to different chemotherapy regimens and number of treatment courses. The study was conducted on 55 CLL patients (44 CLL and 11 CLL/SLL; small lymphocytic lymphoma) and 40 healthy individuals as control, over three-months period. The RNA was extracted by exploitation total RNA extraction kit, treated with DNAse, then cDNA was synthesized and qRT-PCR used to analyze antiapoptotic BCL2 and tumor suppresser p53 gene expressions. Results: CLL/SLL showed higher BCL2 and p53 gene expression than CLL. The patients with CLL showed three-fold increase in BCL2 gene expression compared to healthy controls (p < 0.05), and 50% decrease in p53 gene expressions (p < 0.05). BCL2 gene expression was higher, particularly, for those who were treated with higher range of treatment courses and combination of fludarabine, cyclophosphamide and rituximab (FCR) regimen. P53 gene expression reciprocally related with BCL2 and vice versa. Conclusions: In contrary to BCL2, p53 gene was extremely expressed in patients treated with chemotherapy agents, particularly after 24­30 months disease duration; suggesting a late expression of p53 during advanced stages of the disease. A proportional change in BCL2 and p53 gene expression was reported with different treatment regimens; Chlorambucil (Clb) decreased and FCR regimen increased BCL2 gene expression. Higher p53 gene expression reported with the Chlorambucil + (Chlorambucil + Prednisolone) regimen (AU)