WWOX and gastric cancer: Low expression or deletion of WWOX, as well as copy number variation, have been associated with increased invasiveness and poor prognosis in various tumors, including lung cancer [83,84], breast cancer [33,85,86], HCC [87], gastric cancer [88], ovarian cancer [89], intrahepatic cholangiocarcinoma [90] and clear cell renal cell carcinoma [91] (Table 2).