To investigate whether the differential expression of IFITM proteins in the two cell lines is responsible for their difference in HCoV-OC43 infection efficiency, we examined IFITM protein expression by Western blotting assays and found the two hepatoma cell lines expressed similar levels of IFITM1 and IFITM2/3 (Fig. 1B). The gene discussed is IFITM2; the disease is hepatocellular carcinoma.