MMP1 and prostate cancer: A total of eight papers with nine independent studies were included in this meta-analysis (Figure 1), of which six studies (Jacobs et al., 2008; dos Reis et al., 2009; Srivastava et al., 2012; Yaykasli et al., 2014; Adabi et al., 2015; Shajarehpoor Salavati et al., 2017) examined the association between MMP-2-1306 C/T polymorphism and risk of prostate cancer and three studies (Albayrak et al., 2007; dos Reis et al., 2009; Tsuchiya et al., 2009) addressed the association between MMP-1-1607 1G/2G polymorphism and risk of prostate cancer.