For example, TBX2 interacts with and requires early growth response 1 (EGR1) to inhibit the tumour suppressor genes N-myc downstream-regulated gene 1 (NDRG1) and cysteine protease inhibitor cystatin 6 (CST6) to promote breast cancer cell proliferation [27,28]. The gene discussed is NDRG1; the disease is breast carcinoma.