Prognostic Value of Phosphatidylinositol-3 Kinase p110 α Protein Expression in Patients with Stage I-III Invasive Breast Cancer.

The prognostic value of phosphatidylinositol-3-kinase p110α, a key catalytic subunit in the PI3K/AKT pathway, in breast cancer remains controversial. This study evaluated its prognostic significance in stage I-III invasive breast cancer. p110α protein expression was detected via immunohistochemistry (IHC) in 161 patient tissue samples. Its association with overall survival (OS) and relapse-free survival (RFS) was analyzed using Kaplan-Meier and Cox proportional hazards models. p110α positivity was detected in 59.0% of specimens and showed significant correlation with histological grade (p = 0.034). Survival analysis revealed that p110α positivity was associated with worse OS (log-rank p = 0.008) and RFS (log-rank p = 0.018). In multivariate analysis, p110α expression was an independent predictor of poor prognosis for both OS (HR = 2.45, 95%CI: 1.25-4.78) and RFS (HR = 2.12, 95%CI: 1.14-3.94). This association with poor prognosis was particularly pronounced in stage I-II, hormone receptor (HR)-positive, and human epidermal growth factor receptor 2 (HER2)-negative subgroups. Supporting evidence from the PROGgeneV2 database showed that high PIK3CA mRNA levels predicted inferior survival in external cohorts. p110α protein expression is an independent biomarker for adverse outcomes in stage I-III invasive breast cancer. Its assessment could improve prognostic evaluation and guide personalized therapy.