After overlapping the 5482 down-regulated mRNA in CRC, and 598 down-regulated proteins in CRC, and the IPFs, we discovered that the expression of six IPFs were both changed at the mRNA and protein levels (Fig. 1f), in which three candidates were mitochondrial genes, including HIGD1A, SUCLG2, and SLC25A24 (Fig. 1g, Additional file 2). Here, SUCLG2 is linked to colorectal carcinoma.