The effect of imatinib therapy on tumor associated macrophages (TAMs) in human gastrointestinal stromal tumor (GIST)

The gene expression profile of TAMs microbead isolated from freshly obtained human GISTs were compared in tumors that were untreated, responding to imatinib (sensitive), or resistant to imatinib (resistant) The Affymetrix Human Genome U133A 2.0 platform was used TAMs were microbead isolated from 12 untreated, 5 sensitive, and 4 resistant tumors. Tumors were obtained freshly from the operating room from consenting patients using an IRB approved protocol. Tumors were digested using collagenase and TAMs isolated using microbead negative selection for KIT, CD3, and CD56 followed by positive selection for CD14.