Expression of nucleolar protein p120 predicts poor prognosis in patients with stage I lung adenocarcinoma

Background: P120 is a proliferation-associated nucleolar protein found in m ost human malignant tumors, but not in resting normal cells. In our previou s studies, the expression of p120 was statistically correlated with the pro liferation capacity in human lung cancer cells and could be a prognostic ma rker for resected lung adenocarcinoma. Patients and methods: The expression levels of p120 in tumors were assessed by immunohistochemistry in 59 patients with stage I lung adenocarcinoma wh o underwent radical resection. Using clinical follow-up data, the prognosti c significance of p120 calculated by labeling indices was evaluated using C ox's proportional hazard model. Results: A mean +/- SD of the labeling index of p120 was 35.3 +/- 14.4%. No significant correlation was found between the expression levels of p120 an d clinicopathological factors. Using a cutoff value of 35% in the labeling index of p120, patients with high expression of p120 experienced early recu rrence and shorter survival compared with those having low expression of p1 20 (P = 0.04). Multivariate analysis revealed that p120 served as an indepe ndent and strongest prognostic factor for resected lung adenocarcinoma (P = 0.033). Conclusion: This article provides the first evidence that the expression le vels of p120 in tumor tissues can be used as an independent and powerful pr ognostic marker for resected stage I lung adenocarcinoma.