Application of the p53 and K-ras Gene Mutation Patterns for Cytologic Diagnosis of Recurrent Lung Carcinomas Combined Analysis with Microdissection and Polymerase Chain Reaction-Single- Strand Conformation Polymorphism

BACKGROUND. Cytologic specimens are one of the most important materials for lung carcinoma diagnosis, because they can be used in mass screening for lung carcinoma and early detection of cancer recurrence by examination of sputum and pleural fluid. METHODS. To prove the potentiality of the cytologic specimens to be subjected to molecular detection of recurrent lung carcinomas, the authors enrolled 16 patients who had undergone surgical treatment for lung carcinoma with recurrence detected by malignant pleural fluid. First, they examined K-ras gene and p53 tumor suppressor gene abnormalities in resected tumors by polymerase chain reaction-based single-strand conformation polymorphism (PCR-SSCP) analysis. Next, using a microdissection method, they investigated the use of cytologic specimens such as pleural fluid for the detection of recurrence by finding the same mutations observed in the initially resected tumor. RESULTS. Seven abnormally shifted bands were detected among six patients by PCR-SSCP analysis of surgical materials. Five of 7 abnormally shifted bands (71.4%) also were detected from microdissected malignant cells in cytologic smears. In two cases, they detected mutations by using single malignant cells in pleural fluid. CONCLUSIONS. The authors successfully detected the same mutations in recurrent cytologic specimens as those in the initially resected tumors by PCR-SSCP analysis. These findings suggest that the p53 and K-ras gene mutation patterns are effective markers for the detection of recurrent lung carcinoma in cytologic specimens.