Significance of cooperation between pathomorphologist and oncologist in the treatment of gastrointestinal stromal tumors (GIST)

Abstract

Gastrointestinal stromal tumors (GIST) are derived from stem cells and cells of Cajal pacemaker cells (the cells
that are responsible for the regulation of gastrointestinal motility, occurring in Auerbach’s plexus and around it). For
the diagnosis of GIST tumors are crucial activating mutations within the KIT or PDGFRA genes (plateled-derived
growth factor receptor a) encoding membrane receptors. In the next 80–95% of GIST states CD117 expression
[1]. It remains the primary marker to confirm the diagnosis of gastrointestinal stromal tumors. It is also important
from the clinical point of view, that the place of mutation in these genes is predictive for the selection of therapy.
Important from a therapeutic point is also to determine whether the tumor at diagnosis is the primary tumor, the
recurrent or metastatic foci of the most common location in the abdominal wall, retroperitoneal, or liver.

The beneficial effect of treatment of patients with Gastrointestinal stromal tumors with imatinib dramatically
changed the prognosis and significantly improved survival in this group of patients. In order to obtain good results
of the therapy is well established histopathological diagnosis complemented by immunohistochemical study
of CD117 and useful antibody panel for differential diagnosis with other mesenchymal tumors. A major test to
confirm the diagnosis is the KIT gene mutation and PDGFRA, which is also a predictor for the treatment of GIST,
especially in tumors with a high risk of aggressiveness.