Importantly, studies by Steele and colleagues have demonstrated that CXCR2 deletion abrogated tumor metastasis in KPC Cxcr2−/− mice, yet, no benefits were noted in the overall or tumor-free survival between KPC Cxcr2−/− and KPC mice with or without gemcitabine treatment [47]. This evidence concerns the gene CXCR2 and neoplasm.