Targeted therapies in breast cancer.

Overexpression, activation, and dysregulation of various membrane receptors, signaling pathways, and other factors occur frequently in human breast cancer. Therapeutic approaches targeting these molecules and the selective estrogen receptor modulators and aromatase inhibitors have been demonstrated to have higher efficacy than conventional therapy agents in the treatment of breast cancer, and to have an extensive potential. A rapid expansion of novel diagnostics and predictive tests designed to select the best target population and to personalize cancer care is occurring, but there remain several significant needs for improving the accuracy and reliability of these tests. The use of unstandardized methods and a widespread concern that inaccuracy in interpretation of assays is leading to an unacceptably high error rate in determining the true status of a potential predictive marker in current clinical practice. A variety of factors, including preanalytic conditions, slide-scoring procedures, and other variables, that may be contributing to current testing error rates must be improved for the standardization of these assay procedures to further enable the highest possible quality of diagnoses for breast cancer patients.