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

## TL;DR

This study shows that higher levels of the p110α protein in early-stage breast cancer tumors are linked to worse survival and more cancer recurrence, suggesting it could help guide treatment decisions.

## Contribution

The study demonstrates that p110α protein expression is an independent biomarker for poor prognosis in early-stage invasive breast cancer.

## Key findings

- Higher p110α levels were associated with shorter overall and relapse-free survival in breast cancer patients.
- p110α positivity was an independent predictor of poor prognosis in multivariate analysis.
- The association was strongest in stage I–II, hormone receptor-positive, and HER2-negative breast cancer subgroups.

## Abstract

Breast cancer outcomes vary widely, and better predictors are needed to guide treatment decisions. p110α is a key protein involved in cell growth signals, often altered in cancer. This study investigated whether the expression levels of p110α protein in tumors could help predict the prognosis of patients with early-stage breast cancer. We analyzed tissue samples from 161 patients and found that higher p110α levels were associated with shorter survival and higher risk of recurrence. This finding was confirmed using separate public data. Measuring p110α could therefore help doctors identify patients with a more aggressive disease, potentially leading to more personalized and effective treatment strategies.

Background: 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. Methods: 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. Results: 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. Conclusions: 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.