Notably, in patients with HR-positive breast cancer, recurrent alterations were identified in PIK3CA, ESR1, and TP53. Patients with ERBB2-positive MBC exhibited prominent alterations in TP53, PIK3CA, and ERBB2, while those with TNBC harbored alterations in TP53 and PIK3CA. Other commonly altered genes included MYC, EGFR, FGFR1, CCNE1, NF1, and ARID1A. In our meta-analysis, we found that a majority (77%) of the included studies focused on analyzing these hotspot genes. This evidence concerns the gene ESR1 and breast cancer.