Likewise, the clinical trials discussed above provide evidence to suggest that ovarian cancers with coexisting PIK3CA and MAPK pathway mutations may be sensitive to PI3K pathway inhibition, whereas colorectal cancers harboring the same repertoire of mutations affecting these genes may be resistant (Di Nicolantonio et al., 2010; Janku et al., 2011, 2012). This evidence concerns the gene PIK3CB and ovarian cancer.