MGMT and gastrointestinal stromal tumor: Thus, a possible effect of alkylating agents on a predisposed fraction of GISTs could have so far escaped detection since (1) we herein prove that MGMT methylation is substantially restricted to rare subsets of these tumors, implying the possibility that a few (or even none) of the limited number of GIST patients enrolled in the abovementioned trials could respond to the administered therapy, and (2) a possible response of some GISTs, bearing an inactivated MGMT, could have escaped detection, given the missed adoption of Choi criteria.