RÉSUMÉ
Objective: To diagnose occult micrometastasis of mediastinal lymph node in patients with non small cell lung cancer (NSCLC) and to evaluate its prognostic significance. Methods: Using assays of reverse transcriptase polymerase chain reaction (RT PCR), two hundred and forty two stations of mediastinal lymph node, which were free from tumor determined by routine histopathological examination (pN 0), from fifty eight patients were studied to detect mRNA for MUC1 gene and diagnose nodal occult micrometastasis. Survival rate was calculated by method of Kaplan Meier and survival difference between patients with and without nodal occult micrometastasis was compared with Log Rank test; Logistic regression analysis was carried to determined independent predictive factors of prognosis. Results: The mRNA for MUC1 gene was identified in twenty three stations of lymph node from sixteen patients (27 6%), and nodal occult micrometastasis was diagnosed in those patients. TNM staging for those patients was up regulated from stage I A～II B to stage III A. The survival rate of 3 year in patients with nodal occult micrometastasis (43.7%) was lower than that in patients without nodal occult micrometastasis (73.8%) (P