Identification of PIK3CA aberrations associated with telomere length in breast cancer

Abstract

PIK3CA (p110α) mutations are the most common alterations in the phosphoinositide 3-kinase (PI3K) pathway, affecting about 27% of breast cancer (BCa) patients. Telomeres play crucial roles in chromosomal maintenance and stability. This study investigated the correlations between telomere length and PIK3CA mutations in BCa patients and compared these findings with the patients' clinical parameters.HRM assay was used to identify the PIK3CA mutations in 89 patients. The mutations were confirmed by Sanger sequencing, and the telomere length was analysed using RT-PCR.Thirty patients were found with mutations in the PIK3CA gene. The frequency of the PIK3CA mutations was also high in the following BCa types: luminal B molecular type, IDC histologic type, T2 stage, node (0) status, ER (+) and PR (+). There was a significantly high frequency of PIK3CA exon 20 mutations in the grade 2 tumours (p = .0272) and a significantly high frequency of PIK3CA exon 9 mutations in the node (0) tumours (p = .0016). In contrast, the telomeres were longer in the tumour tissues than in the healthy tissues (p = .3622). Moreover, in the tumours with the PIK3CA mutations, the telomeres were significantly longer than in the tumours that did not carry any PIK3CA mutations (p = .0118). The telomere length was also significant in the node (0) status tumours (p = .0253).These results suggest that longer telomeres may be a risk factor for BCa. An association was found between PIK3CA mutations and longer telomere length in BCa. Telomere length and PIK3CA in BCa may be developed as potential prognostic or diagnostic biomarkers for BCa risk prediction.