Among four different tumor-infiltrating DP myeloid subpopulations, only two subsets; P1a; CD11bhi Gr-1dim F4/80+ cells and P2a; CD11blo Gr-1dim F4/80- cells stained positive for iNOS whereas the Gr-1int CD11bint F4/80- (P3) and the Gr-1hi CD11bhi F4/80- (P4) populations did not (Figure 1A). Here, NOS2 is linked to neoplasm.