MMP2 and gastric cardia carcinoma: In addition, recent studies reported that a series of gene mutation such as adenosine diphosphate ribosyltransferase (ADPRT) and X-ray repair cross-complementing 1 (XRCC1), matrix metalloproteinases 2 (MMP-2), and cyclooxygenase-2 (COX-2) were only associated with the gastric cardia cancer [20–22].