Aberrations of the p 53 gene in roentgenographically occult squamous cell carcinoma of the lung

Mutations of one p 53 allele and LOH occur in advanced lung cancers, but in early lung cancer these things were not known well. To make clear carcinogenesis of lung cancer, it is important to study p 53 alterations in early lung cancers. We studied them in 29 roentgenographically occult lung cancers by means of PCR-SSCP and microsatellite marker. PCR-SSCP was performed for exon 7 of the p 53 gene. LOH was found in 6 cases and point mutation was found in 2 cases (codon 234 T-A transversion, codon 245 G-T transition). Frequency of LOH and point mutations was lower than in the cases of advanced lung cancers. These things suggested the clonal expansion of aberrant p 53 gene occurred in the course of cancer development (i.e., roentgenographically occult lung cancer to advanced lung cancer).