p53 and c-myc alterations in patients with non-small cell lung carcinoma in Serbia.

Purpose: To determine the incidence of c-myc amplification and p53 mutations in patients with stage I, II and III of histologically confirmed non-small cell lung cancer (NSCLC) of different histological subtypes: adenocarcinomas (AC), squamous cell carcinomas (SCC), large cell carcinomas (LCC) and adeno-squamous carcinomas (AC-SCC) and of histological grade (G) 2 and 3.
Materials and Methods: DNA was isolated from 41 frozen tumor samples by standard phenol-chloroform extraction. Amplification of c-myc gene was determined by the differential polymerase chain reaction (PCR) method, followed by polyacrylamide gel electrophoresis, and mutations in exons 5, 6, 7 and 8 p53 gene were detected by the PCR single-strand conformation polymorphism (SSCP) method.
Results: c-myc gene amplification was found in 2 of 41 (4.9%) analyzed tumors and both amplifications were found in stage III tumors. Mutations in the p53 gene were found in 19 of 41 (46.3%) of the analyzed tumors. SCC and LCC were more likely to contain mutations in p53 gene (68.4% and 66.7%, respectively).
Conclusion: Our results indicate that p53 mutations are common in NSCLC with higher incidence in SCC compared with other histological subtypes. Since the mutations are more frequent in early-stage NSCLC, it appears that mutations in p53 gene could be an early event in lung carcinogenesis. On the other hand, c-myc amplification is a rare event in NSCLC and occurs in the late phase of development of this type of lung cancer.