KIT and mesenchymal cell neoplasm: Since GIST has now been accepted as a separate tumour entity and is defined as a spindle cell, epithelioid or pleo-morphic mesenchymal tumour of the gastrointestinal tract that strongly expresses the KIT (CD 117) protein and may harbour mutations of the type III tyrosine kinase receptor gene (either KIT or PDGFRA) [59].