Molecular tests such as the 21 gene expression test (Oncotype DX(TM)) and 70 gene microarray test (MammaPrint(®)) have revolutionized the predictive and prognostic tools in the clinic. By stratifying the risk of recurrence for patients, the tests are able to provide clinicians with more information on the treatment outcomes of using chemotherapy, HER2 targeted therapy or endocrine therapy or the combination of the therapies for patients with particular genetic expressions.