In the second edition of this Special Issue, several promising antitumor strategies have been presented in addition to those reported in the first edition, in which several compounds (acetylcorynoline, BaP1, sarco/endoplasmic reticulum calcium ATPase inhibitors, neuropeptide Y, neuropeptide Y antagonists, neurokinin-1 receptor antagonists) exerting antitumor effects against colorectal cancer, papillary thyroid carcinoma, cholangiocarcinoma, Ewing sarcoma, liver cancer, and breast cancer were reported [...]. Here, NPY is linked to breast cancer.