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

P120 is a proliferation-associated nucleolar protein found in most human malignant tumors, but not in resting normal cells. In our previous studies, the expression of p120 was statistically correlated with the proliferation capacity in human lung cancer cells and could be a prognostic marker for resected lung adenocarcinoma.

The expression levels of p120 in tumors were assessed by immunohistochemistry in 59 patients with stage I lung adenocarcinoma who underwent radical resection. Using clinical follow-up data, the prognostic significance of p120 calculated by labeling indices was evaluated using Cox's proportional hazard model.

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 and clinicopathological factors. Using a cutoff value of 35% in the labeling index of p120, patients with high expression of p120 experienced early recurrence and shorter survival compared with those having low expression of p120 (P = 0.04). Multivariate analysis revealed that p120 served as an independent and strongest prognostic factor for resected lung adenocarcinoma (P = 0.033).

This article provides the first evidence that the expression levels of p120 in tumor tissues can be used as an independent and powerful prognostic marker for resected stage I lung adenocarcinoma.