Expression of caveolin-1 is associated with poor prognosis of patients with squamous cell carcinoma of the lung

Background: Caveolin-1, as a major component of caveolae, is involved in the regulation of cell cycle by impacting various signaling pathways. Previous studies of caveolin-1 in cancer showed two contrary results. In most in vitro studies, caveolin-1 played a role as a tumor suppressor. On the other hand, the elevated expression of caveolin-1 was often reported to be associated with poor clinical outcome in human studies. These results indicate differential biological functions of caveolin-1 depending on the development and progression stage of cancer in vivo. Methods: To clarify the correlation between the clinicopathologic profiles of pulmonary squamous cell carcinomas and the expression of caveolin-1, 107 cases of formalin-fixed and paraffin-embedded tissues of pulmonary squamous cell carcinomas were immunohistochemically evaluated for the expression of caveolin-1 by the tissue-array method. Results: Caveolin-1 was expressed in 34 cases (31.7%) among 107 cases of pulmonary squamous cell carcinoma. The expression of caveolin-1 was statistically correlated with pathologic stage (stage I and II vs. III; P<0.001), pT (T1 and T2 vs. T3 and T4; P=0.001), and pN (N1 vs. N2 and N3; P=0.0143). The patients with caveolin-1 expression in pulmonary squamous cell carcinomas showed a poorer prognosis than those in caveolin-1-negative group (P=0.0345). Conclusion: The expression of caveolin-1 is significantly correlated with advanced pathologic stage and poor prognosis in pulmonary squamous cell carcinoma. The results of current study suggest that the expression level of caveolin-1 may be a candidate factor for predicting prognosis in patients with pulmonary squamous cell carcinoma.