Analysis of p53 tumor suppressor pathway genes in chronic lymphocytic leukemia.

The p53 tumor suppressor gene plays an important role in preventing tumor development. The p53 protein interacts with other p53 signal pathway members to control cell proliferation. In this study, expression of the p53, Human homolog of murine Double Minute 2 (HDM2), p14Alternating Reading Frame (ARF), Zinc Finger and BTB domain containing 7A (ZBTB7A), and B-Cell Lymphoma 6 (BCL6) genes was quantitatively investigated by real-time polymerase chain reaction (PCR) in the peripheral blood of patients with chronic lymphocytic leukemia (CLL) and healthy controls. Plasma fibronectin levels were determined by enzyme-linked immunosorbent assay. Expression of the p53, p14, and HDM2 genes were significantly higher in the patients. However, ZBTB7A and BCL6 gene expression was not detectable in both groups. A positive correlation between p14ARF and HDM2 expression and a negative correlation between p53 and p14ARF expression was observed. Expression of the p14ARF and HDM2 genes were inversely correlated in the control group. Neither HDM2 nor p14ARF gene expression was correlated with p53 expression. The p53 gene was also analyzed for the presence of mutations. A splice-site mutation was found in a single patient. Our findings indicate that expression of the p53, p14ARF, and HDM2 genes are associated with CLL. Elucidation of the mutual interactions at the protein level warrants further studies.