CMTM7 protein levels are low in the malignant tissues of various cancers such as those of esophagus, stomach, pancreas, liver, lung, cervix, and breast. as compared with its expression in the normal tissues of these organs. Furthermore, the forced overexpression of CMTM7 protein in various cancer immortalized cell lines inhibit their proliferation and motility in culture as well as their ability to form tumors in a nude mouse experimental model of cancer. These findings suggest that the CMTM7 protein acts to inhibit the development and/or progression of these cancers and therefore that the CMTM7 gene acts as tumor suppressor in these cancers. However, further studies are needed to support these suggestion and determine if expression of the CMTM7 can be used as a clinical marker of these cancers severity/prognosis and/or as therapeutic targets for treating them.