The majority of patients with breast cancer had triple-negative (ER, PR and HER2 negative; n = 30; 46.9%), followed by estrogen receptor (ER) -positive and/or progesterone receptor (PR) -positive, human epidermal growth factor receptor 2 (HER2) -negative (luminal-like) (n = 28; 43.8%), or HER2 positive, ER-negative, PR-negative disease (n = 5; 7.8%) at the time of the MTB case discussion; one patient (1.6%) had triple-positive disease (ER positive and/or PR positive, HER2 positive). The gene discussed is ESR1; the disease is breast cancer.