MTOR and gastric cancer: MiR-21 regulates cisplatin resistance of GC cells through the PI3K/Akt/mTOR pathway.[63] MiR-421 was involved in regulating 5-fluorouracil and gemcitabine resistance in MGC-803 GC cell lines and pancreatic cancer cell lines.[64,65] The sensitivity of GC cells to cisplatin and trastuzumab was regulated by miR-223/FBXW7 axis.[66,67] Therefore, the purpose of this study was to compare the diagnostic value of these 4 miRNAs in GC.