Compositions and methods for predicting response and resistance to cdk4/6 inhibition

A method of monitoring therapeutic efficacy of inhibition of CDK4/6 in a subject with neoplasia comprising:

• administering an effective amount of a CDK4/6 inhibitor to the subject;
• obtaining a first test sample from the subject;
• determining the expression level of a micro ribonucleic acid (miRNA) in the test sample;
• comparing the expression level of the miRNA in the first test sample with the expression level of the miRNA in a reference sample;
• and
• determining whether the CDK4/6 inhibitor will inhibit neoplasia in the subject if the expression level of the miRNA in the first test sample is differentially expressed as compared to the level of the miRNA in the reference sample.