TP53 gene mutation; denaturing high performance liquid chromatography; exon; codon
Laboratory Medicine Online, v.1, no.4, pp.202 - 208
Background: Lung cancer is one of the leading causes of cancer-related deaths throughout the world. The gene tumor protein 53 (TP53) is frequently mutated in cases of lung cancer. This study was performed to investigate the frequencies and types of mutations in the TP53 gene in Korean patients with lung cancer.
Methods: We obtained tissue samples from 80 lung cancer patients and synthesized TP53 cDNA by using RNA isolated from these tissues by performing reverse transcriptase polymerase chain reaction. Hybridization and denaturing high-performance liquid chromatography were performed to identify the TP53 gene mutations, and then, the mutations were validated by direct sequencing.
Results: Forty mutations out of the 80 patients (50.0%) were noted in the TP53 gene. The frequencies of TP53 gene mutation for different cancer types, namely, squamous cell carcinoma, adenocarcinoma, and small cell carcinoma were 61.1%, 27.3%, and 26.7%, respectively. The mutation frequencies in the different regions of the gene were 10.0% for exon 4, 35.0% for exon 5, 12.5% for exon 6, 22.5% for exon 7, 17.5% for exon 8,and 2.5% for exon 9. The frequently mutated positions were codon 179 in exon 5, codons 202 and 220 in exon 6, and codons 266 and 273 in exon 8.
Conclusions: Exon 5 was the most frequently mutated region in the TP53 gene. Compared to the patients with the other types of cancers, patients with squamous cell carcinoma showed a higher frequency of TP53 mutation. Codon 179 was the most frequently mutated codon in the TP53 gene.