İBRAHİM HALİL ERDOĞDU, DUYGU GÜREL
Meandros Medical and Dental Journal - 2023;24(4):309-314
Objective: There have been new developments in determining the development, treatment, and prognosis of breast cancer. In particular, determining the characteristics of breast cancer at the molecular level has become crucial in the initiation of new therapies. In recent years, the detection of PIK3CA mutations in breast cancer, as in many types of cancers, and especially in cases that have become resistant to treatment, is guiding the use of new targeted drugs. Therefore, the aim of this study was to evaluate PIK3CA mutations in patients with breast cancer. Materials and Methods: In this study, PIK3CA mutations were detected using next-generation sequencing technology applied to paraffin-fixed, paraffin-embedded samples of primary tumor tissue from 110 breast cancer patients who did not receive neoadjuvant treatment previously. The relationship between PIK3CA mutation and tumor molecular subtypes, immunohistochemical estrogen receptor (ER), progesterone receptor (PR), c-erbB2, Ki-67 staining, and human epidermal growth factor 2 (HER2)Neu status detected by fluorescence in situ hybridization were investigated. Results: The PIK3CA mutation was found in 21 (19.1%) cases. A significant positive correlation was detected between ER, PR, and luminal A type and PIK3CA mutations (p<0.05). PIK3CA mutation was not observed in any case with triple negative type. No statistically significant correlation was found with other clinicopathological parameters. The most common PIK3CA mutation subtypes were H1047R and E542K. Conclusion: The results of our study showed that PIK3CA mutations were observed at significantly higher rates in hormone receptor-positive patients, but PIK3CA mutations may be less frequently observed in HER2+ patients.
