MMP1 and gastric cancer: For the second pair of networks, previous studies have shown that (i) both CML and gastric cancer might co-exist in a single patient (Butala, Kalra & Rosner, 1989), which might be due to decreased immunity (Mangal et al., 2018), and (ii) clinicians are recommended to pay attention to the association of CML and gastric cancer (Mokhtarifard et al., 2016) and expression of MMP1 may contribute to gastric cancer formation (Yang et al., 2017).