Changes in ER or Her2 receptor expression were seen in two patients: cancer cells from patient 14 of the ER+ Her2- group transformed into the TN phenotype at month 8, and patient 15 who had ER+ Her2+ disease at the time of diagnosis lost Her2 expression on a tumor biopsy performed in month 49 (Supplementary Data and Table S1). The gene discussed is ESR1; the disease is cancer.