To determine whether Cxcr2 is also important in NRasQ61R/Ink4a−/− melanoma tumors, we crossed Tyr-CreER + ::NRasQ61R/Ink4a−/− mice [34] with the Cxcr2fl/fl mice [24] to produce Tyr-CreER+::NRasQ61R/Ink4a−/−::Cxcr2−/− (NRas/Ink4a/Cxcr2−/−) and Tyr-CreER+::NRasQ61R/Ink4a−/−::Cxcr2WT (NRas/Ink4a/Cxcr2WT) littermates. The gene discussed is CXCR2; the disease is melanoma.