CXCL12 and gastric cancer: Recent studies have shown that the serum concentration of SDF-1, HGF, and VEGF is elevated in patients with several types of cancers, including breast, liver or ovarian cancer [29,30,31], and what is important is that it was shown that GC tumor mass secretes VEGF and it may serve as biomarker for disease progression and remission [32,33].