NPY and neoplasm: Notably, the up-regulation of Npy expression in KPR172HC cells compared to KPfloxC cells (Fig. 4Bi) was enhanced compared to our immunohistochemical results in tumors (Fig. 1C), suggesting that Npy expression may depend on the local tumor microenvironment and/or an enhancement of Npy expression in KPR172HC cells upon backcross with the C57BL/6J background.