CXCR2 and neoplasm: Although AZD-5069 treatment did not affect the proliferation level of spheroids in the “separated” scenario (59% vs. 57%, p > 0.9999) (Fig. 5a,b), we found a significant reduction in the proliferation level of spheroids from 79 to 54% (p < 0.0001) by AZD-5069 treatment in the “contact” scenario (Fig. 5a,b), meaning that the attenuation of tumor spheroid proliferation by CXCR2 inhibition is dependent on contact with dHL-60 cells.