TACSTD2 and neoplasm: Recently, we demonstrated that the restricted HCV RNA replication within the tumor [41] was associated with the downregulation of tumor-associated calcium signal transducer 2 (TACSTD2), the second most downregulated gene in primary HCV-HCC tissue, which is essential for maintaining the proper cellular localization of CLDN1 and OCLN, two major HCV-entry cofactors [43].