STIP1 and cancer: In addition, recent studies have demonstrated that STI1/HOP levels are increased in a large number of cancer cell types (Sun et al., 2007; Walsh et al., 2009, 2011; Kubota et al., 2010; Wang et al., 2010; Sims et al., 2011; Tsai et al., 2012), and that the increased STI1/HOP function is associated with cancer cell proliferation and migration (Kubota et al., 2010; Horibe et al., 2011, 2012; Li et al., 2012b; Willmer et al., 2013).