PIK3CA and breast carcinoma: The PIK3CA rs121913279 (p.H1047R and p.H1047L) was among the hotspot mutations indicative of the use of alpelisib, a PI3Kα-specific inhibitor while Figure 3 showed that 22 out of 31 HR+/HER2- breast cancers harbored PIK3CA missense mutations [36].