“…As shown in Figure 1, a total of 14 studies were finally identified (Nieters et al, 2006;Etokebe et al, 2009;Purdue et al, 2009;Ashton et al, 2010;Balistreri et al, 2010;Gast et al, 2011;Zeng et al, 2011;Junjie et al, 2012;Kim et al, 2012;Nischalke et al, 2012;Slattery et al, 2012;Yang et al, 2012;Pimentel-Nunes et al, 2013). For the +597T>C polymorphism (rs3804099), 8 studies were available, including a total of 3987 cases and 5079 controls.…”