Background & objective: Metastasis is one of the most important factors in determining the prognosis of lung cancer patients. However, it is difficult to determine single cancer cell in lymph nodes by routine methods. This study was designed to investigate a sensitive method for detecting lymph node micrometastases in human lung carcinomas.
Methods: Mutation detection for p53 gene (exon 5-8) was performed in 39 cases of primary lung carcinomas and 110 corresponding lymph nodes (LNS) by PCR-TGGE method. Serial sectioning was performed to confirm micrometastases in some of these samples.
Results: p53 mutations were found in 23 of 39 cases with primary lung cancer. Forty LNSs showed p53 mutation in 67 corresponding LNSs. They were located at the same exon as their primary tumors. Only twenty-six LNSs were detected metastases by routine histopathology. Forty-three LNSs from sixteen cases of primary tumor without p53 mutation and ten LNSs from the patients without tumor disease did not have any p53 mutations. By PCR-TGGE assay p53 gene mutations were determined in fourteen LNSs without histopathological evidence of metastasis. Micrometastases were found in four of the serially sectioned cases.
Conclusion: Mutation detection for p53 gene (exon 5-8) showed lymph node micrometastases in patients with lung carcinoma. It may be used as a complement for the routine histopathology.