Drugs producing DIGO, i.e., phenytoin, nifedipine and cyclosporin A, stimulate the proliferative capacity of keratinocytes, accompanied by elevated levels of a cell proliferation marker, Ki67, and basic fibroblast growth factor (bFGF) or keratinocyte growth factor (KGF) in gingival hyperplasia [58,59,60,61,62]. This evidence concerns the gene FGF2 and gingival disorder.