A study by Matsusaka et al., 2015 conducted to evaluate the effect of CXCR4 variants on patients with metastatic colorectal cancer revealed that patients with rs2228014 AA have a significantly shorter progression-free survival (PFS) than patients with the GG genotype (10.5 vs. 9.6 months, HR (95% CI) 1.40 (1.02–1.93), p = 0.035) [34]. The gene discussed is CXCR4; the disease is metastatic colorectal cancer.