ESR1 and breast cancer: When adjusted for standard of care (ESCAT I‐II) genes (i.e., PIK3CA, ESR1, and ERBB2 for breast cancer; KRAS, NRAS, and BRAF for colon cancer, etc.), 37 (3.6%), 0 (0%), 1 (0.2%), and 0 (0%) of mutant alleles would have been negative among breast, bowel, lung, and skin cancer samples, respectively.