The proteins p110α and p110β are isoforms of the catalytic subunit of class I phosphoinositide 3-kinases (PI3Ks). Class I PI3Ks are involved in the regulation of cell survival, growth, proliferation, and migration, and their aberrant activation contributes to the oncogenesis of various human cancers. In this study, we assessed expression of p110α and p110β in non-small cell lung cancer (NSCLC) and their association with clinicopathological factors and patient survival. Seventy-six NSCLC cases

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... re analyzed by immunohistochemical staining for p110α and p110β. Of the 76 tumors, 18 (23.7%) and 43 (56.6%) were classified in the high p110α and p110β expression groups, respectively. Expression of p110α was higher in smokers compared with non-smokers (P = 0.042). No other clinico-pathological factors showed significant association with p110α or p110β expression. In univariate and multivariate survival analyses, high p110β expression was associated with worse overall survival (OS) in stage I NSCLCs (P < 0.001), whereas the high p110α expression group had shorter OS in stage II to IV NSCLCs (P = 0.005). Our results suggest that p110α and p110β play different roles depending on tumor stage, and that both p110α and p110β have potential as independent prognostic biomarkers of NSCLC.