PTK2 and gastric cancer: Many previous studies reported that expression of total (phosphorylated and nonphosphorylated) FAK and/or the phosphorylated form of FAK at tyrosine 397 (pFAK-Y397) can be prognostic predictors in various types of malignant tumors including colorectal cancer [13], non-small-cell lung carcinoma [17], breast carcinoma [18], hepatocellular carcinoma [19,20], cervical cancer [21], glioma [22], epithelial ovarian carcinoma [23], endometrial carcinoma [24], and gastric cancer [25].