AKT1 and gastrointestinal stromal tumor: MiR-218. According the findings of a study by Fan and colleagues, the expression of miR-218 was down-regulated in an imatinib-resistant GIST cell line, whereas miR-218 overexpression was able to restore the sensitivity of GIST cells to imatinib, with the PI3K/AKT signaling pathway possibly involved in the mechanism.