APOD and gastric cancer: I. This intestinal gastric cancer progression signature (iGCPS) included genes encoding secreted proteins (apolipoprotein D - ApoD), ECM proteins (collagen 1 – Col1, follistatin-like 1 – Fstl1, lumican–Lum, secreted protein acidic and cysteine rich - Sparc), and a regulatory protein that participates in receptor-mediated signal transduction (GTP-binding protein overexpressed in skeletal muscle–Gem).