Downregulation of phosphatidylethanolamine binding protein 1 associates with clinical risk factors in gastrointestinal stromal tumors, but not with activation of the RAF-1-MEK-ETV1 pathway

Aim of this study was to investigate phosphatidylethanolamine binding protein 1 (PEBP1) in GIST and its relations with MEK1/2 activation and ETV1 by immunohistochemistry. Loss of PEBP1 was found in 22/161 (13.7%) GIST, was associated with clinical risk factors and with a trend towards shorter disease free survival, but not with pMEK1/2 and ETV1 expression. So downregulation of PEBP1 does not activate the Ras-Raf-1-MEK1/2-ERK1/2 pathway by phosphorylation of MEK1/2 and does not influence ETV1 expression in GIST. Loss of PEBP1 associates with clinical risk factors, but since no significant influence on survival was found, further studies are required.

► We investigated downregulation of phosphatidylethanolamine binding protein 1 (PEBP1) in a large series of GIST.
► PEBP1 downregulation was associated with clinical risk factor for recurrence.
► Downregulation of PEBP1 does not activate the Ras-Raf-1-MEK1/2-ERK1/2 pathway by phosphorylation of MEK1/2 in GIST.
► PEBP1 downregulation does not influence ETV1 expression in GIST.