Differential expression of PI 3 K isoforms and correlation with clinicopathological factors in patients with gastric cancer

Activation of phosphoinositide 3-kinase (PI3K) is pivotal for the oncogenic PI3K/AKT signaling pathway. This study assessed the differential expression of PI3K isoforms in gastric cancer and correlation with clinicopathological parameters. Tissue microarray blocks were generated from 153 gastric cancers and immunohistochemically stained for 4 PI3K isoforms: p110α, p110β, p110γ and p110δ. Isoform p110α was more highly expressed in tumors with a diameter less than 4 cm (P=0.009); lower pathological T (pT) stage (P<0.001), N stage (P=0.001), or TNM stage (P<0.001); and no lymphovascular invasion (P=0.001); p110β was significantly associated with advanced pT stage (P=0.028) and lymphovascular invasion (P=0.014). High p110α expression significantly correlated with longer overall survival (OS) (P=0.007) and recurrence-free survival (RFS) (P=0.048), whereas high p110β expression correlated with shorter OS (P=0.008) and RFS (P=0.058). In addition, p110β was an independent factor for poor prognosis in multivariate analysis for OS. Neither p110γ nor p110δ expression showed clinicopathological significance. These results suggested that p110β might be more important for the development and progression of gastric cancer than other PI3K isoforms and had potential as a prognostic biomarker in patients with gastric cancer.