A method of treating leukemia in a patient, the method including obtaining a plasma sample from a patient at a first time point and at a second time point, measuring a gene expression level of a set of core clock genes, and at least one of a first set of peripheral clock genes and a second set of peripheral clock genes, each in the plasma sample at the first time point and in the plasma sample at the second time point. Then determining that a first treatment is effective or ineffective for the patient when a correlation of the gene expression level of the set of core clock genes, the first set of peripheral clock genes, and the second set of peripheral clock genes, and treating the patient accordingly.