In our laboratory breast cancer analysis, two retrocopies with differential expression characteristics for the ER+ (estrogen receptor-positive) subtype, AC098591.2, and PABPC4L, and 7 downregulated retrocopies in the TNBC (triple-negative breast cancer) subtype, RAB6C, RPS16P5, RHOB, MEIS3P2, PGAM1P5, HMGN2P15, and KRT8P13, were identified [89]. Here, ESR1 is linked to breast cancer.