Detection of P53 Codon 72 Polymorphism in Lung Cancer Patients by Real Time Polymerase Chain Reaction - SimpleProbe Probe Aassay

The P 53 tumor suppressor gene (P 53) is a key gene involved in cancer control by producing P 53 protein to inhibit proliferation and enhance apoptosis of cancer cells. It has been reported that the polymorphism at the codon 72 on the exon 4 of P 53 resulted in 3 different genotypes of the P 53: Arginine/Arginine (Arg/Arg), Arginine/Proline (Arg/Pro) and Proline/Proline (Pro/Pro) genotypes, and found that individual with Pro/Pro of P 53 codon 72 polymorphism had a higher risk for lung, bladder and nasopharyngeal cancers than those with Arg/Arg. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay used to detect P 53 codon 72 polymorphism is not suitable for a mass screening since it is complicated, time-consuming and at risk for carcinogen exposure. Recently, real-time polymerase chain reaction-SimpleProbe probe (R-PCR-SP) assay has been suggested to be suitable for a mass screening of various genetic polymorphisms with a faster and safer way. The aim of this study is to detect P 53 codon 72 polymorphism in Thai patients with lung cancer by the R-PCR-SP assay using SimpleProbe probe and melting curve analysis and the PCR-RFLP assay. The findings from these two methods were then comparable. Seventy DNA samples from peripheral blood leukocyte of lung cancer cases were recruited in this study. The results of P 53 codon 72 polymorphism detected by the R-PCR-SP and the PCR-RFLP assays were completely accordant ( κ= 1.0 , 95% CI = 1.0-1.0). The findings demonstrated 12 individuals with Arg/Arg, 41 cases with Arg/Pro and 17 cases with Pro/Pro. In addition, we found that the R-PCR-SP assay was a faster and safer method for detection of P 53 codon 72 polymorphism than the PCR-RFLP assay. Results of the present study suggest that the R-PCR-SP assay with SimpleProbe probe and melting curve analysis may be a useful screening tool for detection of P 53 codon 72 polymorphism in the high risk group of lung cancer in Thais.