We found that (i) ITGA4 is highly expressed in GISTs, (ii) decreased ITGA4 signalling blocks GIST cell invasion in vitro, (iii) ITGA4 protein expression is associated with some adverse prognostic features in GIST such as a high mitotic count, presence of tumour necrosis and metastatic disease and (iv) GIST ITGA4 protein expression is associated with unfavourable survival outcome. The gene discussed is ITGA4; the disease is gastrointestinal stromal tumor.