Results of multicenter testing of PIK3CA somatic mutations in hormone-receptor positive HER2-negative advanced breast cancer

Aim: Activating somatic mutations in p110α catalytic subunit of PIK3-kinase (PIK3CA) are present about 40% breast cancers (BC), and involved oncogenesis cancer growth. PIK3CA inhibitor therapy is approved for patients with advanced HR+/HER2- endocrine-resistant BC mutations. Such targeted improved patient disease-free survival. Method: Analyses gene were performed five University Hospital Centers Croatia. Qualitative detection was on DNA extracted from 507 samples, by the real-time PCR method using Cobas® mutation test. Results: detected 209 (42.2%) out 495 successfully analyzed cases. In 12 cases (2.4%), tumor tissue not sufficient quality analysis. Most helical (41.2%) kinase domains (46.9%) protein. The most frequently H1047L/R/Y (46.4%), E545A/D/G/K (26.3%) E542K (13.9%), followed N345K (8.1%). 44.8% primary 39.6% metastatic lesions (χ2=0.647; P=0.421). age did significantly affect percentage (χ2=0.543; P =0.461). Institutions differed number cases, but (χ2=6.23; df=4; P=0.183) nor frequency common (χ2=2.65; P=0.618). Conclusion: frequencies correspond to those reported literature. We have shown that as well suitable analysis, a significant obstacle