Fig. 2

Overexpression of PKA catalytic subunit alpha and its clinical significance Kaplan–Meier analysis of overall survival and relapse-free survival by low, medium, and high PKA Cα (PRKACA) expression. Overall survival analysis (A, GSE4373, p = 0.024; B, GSE17710, p = 0.001) and relapse-free survival (C, GSE17710, p < 0.001) of the patients with squamous NSCLC were performed using Cox proportional hazard models and follow-up data for the indicated period. The result was as follows. The blue line indicates the group with low PRKACA expression ((a) n = 43, (b) n = 18, (c) n = 18) and the green line indicates the group with medium PRKACA expression ((a) n = 43, (b) n = 19, (c) n = 19). The red line indicates the group with low PRKACA expression ((a) n = 44, (b) n = 19, (c) n = 19). D Representative immunohistochemical analysis for PKA activity scored by P-PKA Cα substrate in the tissue microarray constructed using samples obtained from 236 NSCLC patients. Scale bar = 50 μm. E Total cell lysates of normal human lung epithelial BEAS-2B cells and four different squamous-cell lung carcinoma (SQC) cell lines (NCI-H1703, HCC95, SK-MES-1, and SNU-1330) were subjected to western blot analysis for the expression levels of P-PKA and PKA Cα. Results are expressed as the means ± SD of three individual experiments. Significance was calculated by the student's t-test (*P < 0.05, **P < 0.01, and ***P < 0.001, vs. lung normal epithelial cells). Data are the means ± SD (n = 3)