Dr. Osborne on Evaluating HER2 Positivity in Breast Cancer

C. Kent Osborne, MD, director of the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine, discusses his take home message for physicians treating patients with HER2-positive breast cancer. Osborne says the role of HER2-positivity is complicated.

Not only should physicians analyze whether the patient is negative or positive of HER2, but Osborne says they should also pay attention to what level of amplification is precent and what percentage of cells are HER2-positive. Evaluating how positive and what percentage of cells are effected is important in making these treatment decisions.

In patients where only 10% to 15% of the cells express HER2, HER2-targeted agents may not be the most appropriate choice. For example, T-DM1 will not be able to reach all cells if they are not all HER2-positive, and there are some data suggesting this is the case, Osborne notes.

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