However, during cancer progression, the accumulation of inducible nitric oxide synthase positive (iNOS+) and CD11b+Gr1+ myeloid cells in the peritumoral region suppresses the contraction of tumor-draining collecting lymphatic vessels (117) (Figure 1), which might diminish tumor antigen transportation and DC trafficking to the TDLNs, reducing the immune response (118). This evidence concerns the gene NOS2 and cancer.