PF4 and medullary thyroid gland carcinoma: MTC was also reported in Cdc42-KO (Figure 2), RhoA-KO, Rock2-KO, and ADF/cofilin-KO mice under the control of a megakaryocyte (MK)-specific promoter (using Pf4-Cre mice) [90,91,102,103,104,105].