Loss of PTEN expression in breast cancer: Association with clinicopathological characteristics and prognosis

Various studies have evaluated the significance of PTEN (phosphatase and tensin homolog deleted from chromosome 10) expression in breast cancer, but their results remain controversial. We conducted a meta-analysis to evaluate the associations of PTEN expression with clinicopathological characteristics and prognosis in breast cancer. PubMed, Embase, Web of Science, and China National Knowledge Infrastructure were searched to identify relevant publications. The associations between PTEN expression and clinicopathological parameters, disease-free survival (DFS), and overall survival (OS) were then assessed via meta-analyses of odds ratio (ORs) and hazard ratio (HRs) with 95% confidence intervals (CIs). Based on 27 studies involving 10,231 patients, the pooled results revealed that PTEN loss was significantly more common in breast cancer than in normal tissues (OR = 12.15, 95% CI = 6.48-22.79, P < 0.00001) and that PTEN loss had clear associations with larger tumor size (> 2 cm, OR = 0.62, 95% CI = 0.48-0.82, P = 0.0006), lymph node metastasis(OR = 0.61, 95% CI = 0.45-0.82, P = 0.0001), later TNM stage(stage III-IV, OR = 0.55, 95% CI = 0.35-0.86, P = 0.009), poor differentiation(OR = 0.37, 95% CI = 0.24-0.59, P < 0.0001), and the highly aggressive triple-negative phenotype (OR = 1.62, 95% CI = 1.23-2.12, P = 0.0005). Moreover, patients with PTEN loss exhibited significantly worse DFS and OS(HR = 1.63, 95% CI = 1.04-2.22, P < 0.00001; HR = 1.41, 95% CI = 1.08-1.73, P < 0.0001; respectively). In conclusion, PTEN loss might predict more aggressive behavior and worse outcomes in patients with breast cancer.