ESR1 and brain neoplasm: The most common somatic variants detected using NGS in the literature included TP53, CDK4, MDM2, RB1, and CDKN2A/B for sarcomas [31], ERBB2, PIK3CA, and ESR1 for breast cancer, EGFR and KRAS for NSCLC, KIT and IDH1/2 for gastrointestinal tumors [12], and TP53, IDH1, PIK3CA, PTEN, and EGFR for brain tumors [32].