Gastrointestinal stromal tumors: a rare nosological entity and a model example for the use of personalized therapy with a molecular basis

Abstract

GIST (gastrointestinal stromal tumor) are stromal tumors of the gastrointestinal tract, belonging to a category of rare tumor called soft tissue sarcoma deriving from the Cajal mesenchymal cells. GIST present a peculiar immunohistochemical profile that is indispensable for a diagnostic confirmation: approximately 80% of cases present a mutation of the c-kit gene which codifies for a trans membrane receptor (antigen CD117) at tirosin-kinasic activity whose activation triggers cell proliferation. About 7% of GIST cases present mutations in the tirosin-kinasic receptor homologous to c-kit, the PDGFRα. Recent studies show that a considerable variety exists in the molecular and genetic characteristics that guide the GIST pathogenesis, therefore allowing the identification of different molecular subtypes of GIST with different prognosis and sensitivities to the specific treatments. The presence of different subtypes in an illness that has been so recently discovered is a model for oncology. With the availability of very active and specific therapeutic agents against molecular alterations which cause the majority of cases of GIST, these tumors have become the models for personalized cancer treatments.