The first variant, p27-Q163* (chr12:g.12871770C>T, c.487C>T), has been identified in two patients with estrogen receptor-positive (ER+) breast cancer [73] and in a further patient diagnosed with invasive urothelial carcinoma (bladder cancer) (COSMIC ID: COSM1299114; ICGC ID: MU4716948) [74]. This evidence concerns the gene ESR1 and breast cancer.