While naïve neutrophils from FVB mice did not significantly reduce the viability of PyMT tumor cells (p = 0.101) (Fig. 2a), addition of exogenous CCL2 did lead to a decrease in viability of the PyMT cells in this co-culture compared to PyMT cells without neutrophils (p = 0.005) (Fig. 2a). This evidence concerns the gene CCL2 and neoplasm.