The prognostic value of TIMP1 as a biomarker in GC is controversial, and its role in tumor invasion and metastasis seems fairly complicated although TIMP1 functions as an inhibitor of matrix metalloproteinases which are highly expressed in cancer and promote tumor invasion and the development of metastatic disease (Bao et al., 2010; Grunnet et al., 2013). The gene discussed is TIMP1; the disease is cancer.