SCN9A and medullary thyroid gland carcinoma: The IC50 values of SV188 in MTC cell lines were 8.47 μM and 9.32 μM against MZ-CRC-1 and TT, respectively and the IC50 of SV188 for INa inhibition of NaV1.7 was 3.6 μM in HEK-293 cells transfected with NaV1.7.