CXCR4 and cancer: CXCR4 has been heavily linked to an increasingly invasive phenotype in a variety of cancers types; however, many of the studies have looked at CXCR4 invasion in only a 2D setting (Guo et al., 2015; Jeong et al., 2014; Niu et al., 2015; Xu et al., 2015; Ying et al., 2015).