Elevated p53 and p21waf1 mRNA expression in blood lymphocytes from lung cancer patients with chemoresistance

Background: Clinical and experimental studies suggest that alteration of the expression level of the p53 gene and other damage responsive genes may be associated with chemoresistance in cancer patients. Methods: The present study evaluated the differences of the basal levels of lymphocytic p53 and p21waf1 mRNA expression collected before receiving cisplatin-based chemotherapy between 48 chemo-ineffective lung cancer patients and 39 chemo-effective lung cancer patients using an optimized semi-quantitative multiplex reverse transcriptase-polymerase chain reaction (RT-PCR). Results: The data indicated that the mean mRNA level of p53 gene in chemo-ineffective patients (0.66) was 26.9% higher than that of the chemo-effective patients (0.52) with statistical significance (P = 0.03), and a significantly higher level of p21waf1 mRNA expression in the chemo-ineffective patients (P = 0.03) was also observed. In addition, by the multiplex long quantitative PCR analysis, we demonstrated that chemo-ineffective and chemo-effective patients have similar amounts of UV damage on their p53 gene of lymphocyte DNA through equal UV treatment. Conclusion: Our results suggest that elevated levels of p53/p21waf1 mRNA in blood lymphocytes collected before chemotherapy may predict the chemoresponses of lung cancer patients.