GEPIA2 (http://gepia2.cancer-pku.cn/#index) showed that CYP1B1-AS1 was downregulated in luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) and basal-like breast cancers (Fig. 1a), but did not differ between these subtypes (Fig. S1b). The gene discussed is CYP1B1; the disease is breast cancer.