Clear examples of genes showing a positive correlation with ER status in breast carcinoma and oestrogen-induced gene expression in ZR-75-1 cells are CCND1, GFRA1, GJA1, IGFBP4, IL6ST, MEIS3, MYB, PDZK1, PGR, SERPINA5 and TFF1 (Fig. 1). The gene discussed is GJA1; the disease is breast carcinoma.