Key Points
• Source: Circulation Research
• Relevance: “We aim to elucidate the prognostic value of PIK3CA mutations and copy number (CN) gain (PIK3CA-mut/gain) in hormone receptor-positive and HER2-negative (HR + /HER2−) breast cancer (BC).”
• Investigators assessed primary HR + /HER2− BC in more than 2000 samples and the links with tumoral and clinical characteristics and outcomes.
• The researchers found that PIK3CA CN gain occurred preferentially in PIK3CA mutant tumors, which aligns with previous research and bolsters the hypothesis of a possible additive effect of mutations and gain to oncogenesis.
• The authors wrote, “We did not find a significant association between gain in PIK3CA and any PIK3CA mutation exons nor we found any association with PIK3CA double mutations or hotspots mutations. Interestingly, we observed a significant increase in PIK3CA CN in metastatic compared to primary tumors in MSK-2018, which might suggest a potential role for PIK3CA CN in the metastatic process. However, a correction for cellularity or other confounding factors was not performed, therefore caution must be taken in interpreting this data.”
• The prognostic value of PIK3CA-mut/gain was independent of grade, size, histological subtype and nodal status.