Abstract: The present invention relates to a method for predicting a response or resistance to and/or a benefit from treatment with an inhibitor of cyclin-dependent kinases 4 (CDK4/6 inhibitor) in a subject suffering from a neoplastic disease, particularly breast cancer, comprising the step of: determining in a sample obtained from said subject the expression level of at least one marker selected from the group consisting of PD-L1, PIAS2, MAP2K6, DSG3, ABCC12, IFT52, ABCB6, ABCC1, ABCA5, ABCC6, ABCC11, CHUK, SUMO1, TDG, AURKA, SMC3, IKBKG and XPC, wherein the expression level of the at least one marker is indicative for predicting the response or resistance to and/or the benefit from the treatment with the CDK4/6 inhibitor in said subject. The invention further pertains to a CDK4/6 inhibitor for use in the treatment of neoplastic disease, particularly breast cancer, in a subject, wherein the subject has been determined to have a benefit from treatment with a CDK4/6 inhibitor in a method of the invention.