To investigate whether hsa_circ_0004085 regulates the level of GRP78 in CRC cells by binding RRBP1, we detected the expression of GRP78 at the mRNA and protein levels and observed that si-RRBP1 decreased the expression of GRP78, whereas overexpression of RRBP1 resulted in the upregulation of GRP78 (Fig. 8A and B). The gene discussed is HSPA5; the disease is colorectal carcinoma.