Expression of ΔNp73 predicts poor prognosis in lung cancer

Purpose: DeltaNp73 is an isoform of the p53 homologue p73, which lacks an NH2-terminal transactivation domain and antagonizes the induction of gene expression by p53/p73. The aim of this study was to detect DeltaNp73 expression in lung cancer and to evaluate the relationship between the DeltaNp73 expression level and the prognosis of patients with resected lung cancer. Experimental Design: We used immunohistochemistry to analyze the protein expression of DeltaNp73 in paraffin-embedded tumor samples from 132 well-characterized lung cancer patients and compared the expression level of DeltaNp73, clinical variables, and survival outcome. Results: Positive expression of DeltaNp73 was detected mainly in the cytoplasm of tumor cells in 77 of 132 patients (58.3%) with lung cancer. The incidence of positive expression of DeltaNp73 was 52.2, 50.0, and 70.2% in patients with stage I, II, and III, respectively (P = 0.04). Positive expression of DeltaNp73 was associated with gender but not associated with age, histologic type, pathological stage, pathological T status, and pathological N status. Lung cancer patients with positive DeltaNp73 expression had a poorer prognosis than those with negative DeltaNp73 expression. In addition, multivariate analysis of the clinicopathological characteristics of lung cancer indicated that positive expression of DeltaNp73 was a significant independent factor for predicting poor prognosis (P < 0.0001, risk ratio = 3.39). Conclusions: Expression of DeltaNp73 may be a useful marker for predicting poor prognosis of patients who underwent resection of lung cancer.