To further validate the above observations, we examined the surface expression of CXCR4 in several different cancer cell lines like DLD-1, HCT- 116, A-549, and MDA-MB-468, where there is negligible or no surface expression of CXCR4 (Fig. 4E), however, CXCR4 protein is present in all the cases in the cytoplasm as observed by confocal microscopy (Fig. 4F). The gene discussed is CXCR4; the disease is cancer.