ESR1 and endometrial cancer: For example, endometrial cancer is characterized by intrachromosomal amplification of ESR1, KRAS, PIK3CA, ERBB2, TERC, MYC, CCNE1 (Rahman et al., 2013; Birkeland et al., 2012; Konopka et al., 2011; Cherniack et al., 2017).