Early detection of tumors is a major determinant of survival of patients suffering from tumors, including gastric tumors. Members of the GTM gene family can be differentially expressed in gastric tumor tissue, and thus can be used as markers for the detection of gastric and other types of cancer. The present invention provides for novel GTMs for the detection of tumors, including gastric tumors, and in particular human zymogen granule protein 16 (ZG16). The GTMs can be used in isolation or together with other known GTMs to provide for novel signatures to be used in the detection of tumors, including gastric tumors.