BNIP3 and hepatocellular carcinoma: BNIP3L and its highly homologous gene BCL2 interacting protein 3 (BNIP3) are mitochondrial outer membrane proteins that are members of the BH3-only protein subfamily in the BCL2 family; they have been reported to function as tumour suppressor genes, and BNIP3 was reported to be silenced by DNA methylation in HCC cells during the development of sorafenib resistance, which intrigued us.