Expression of nm23-H1 gene product in mediastinal lymph nodes from lung cancer patients

Objective: Although numerous studies have shown that nm23-H1 gene product expression is inversely related to metastatic potential in some cancers, the expression in lymph nodes has not been studied in detail. An analysis of nm23-H1 gene product expression in mediastinal lymph nodes from lung cancer patients is reported. Methods: One hundred and thirty-four, randomly selected lymph nodes (63 with positive pathological lymph node status) from 39 surgically treated lung cancer patients were examined. Expression of nm23-H1 gene product was determined using specific monoclonal antibodies. Metastatic cancer cells were highlighted using anti-cytokeratin antibody. Results: Expression of nm23-H1 gene product in patients with less and more than 50% nodes-positive was 12/23 (52.2%) and 15/16 (93.8%) cases, respectively. Immunohistochemical studies with cytokeratin revealed micrometastasis in 6/39 (15.4%) patients and 9/71 (12.7%) nodes previously reported as cancer negative. Expression of nm23-H1 gene product in micrometastasis and metastasis-positive nodes was 5/9 (55.6%) and 55/63 (87.3%), respectively. We also found nm23-H1 gene product expression in germinal center cells. However, we found no relationship between expression of nm23-H1 gene product in germinal center cells and extent of metastasis. Conclusions: Our study demonstrates a positive relationship between expression of nm23-H1 gene product and extent of metastasis in mediastinal lymph nodes from lung cancer patients. Our data for normal germinal center cells suggests that nm23-H1 gene product expression does not play a specific biological role in suppressing tumor metastasis in lung cancer.