ERBB2 and B-cell chronic lymphocytic leukemia: Early successes in predictive biomarkers focused on single mutations, such as the BCR-ABL translocation observed in chronic lymphocytic leukemia or oncogene amplification, such as Her2-neu or EGFR. In the last half decade, therapies targeting tyrosine kinase mutations in lung cancer or high expressing immune markers in many tissue types have become standard of care.