We show that the knockdown of FURIN suppresses tumor growth, proliferation, migration, invasion, spheroid growth, and progression of epithelial‐to‐mesenchymal transition (EMT) in B‐Raf proto‐oncogene, serine/threonine kinase (BRAF) mutant cells, whereas its overexpression in BRAF wild‐type PTC cell lines reversed the effect. This evidence concerns the gene MARK2 and neoplasm.