PTK2 and gastric cancer: Mountain studies have shown that miRNAs played critical roles in tumor proliferation, apoptosis, invasion, metastasis and drug resistance [5], etc. For example, miR-203 inhibits proliferation, migration and invasion of gastric cancer cells by downregulating Slug [6]; miR-1244 inhibits tumor metastasis by targeting FAK in intestinal-type gastric cancer [7]; miR-200c functions as a tumor suppressor in gastric cancer and overcomes drug resistance during cisplatin chemotherapy [8].