Presumably this means an increased number of patients will need Herceptin across the BBB.

Updated guidelines for breast cancer increase number of patients who test HER2-positive
Published on July 28, 2016 at 3:40 AM

Changes to HER2 testing guidelines for breast cancer in 2013 significantly increased the number of patients who test HER2-positive, according to a new study by Mayo Clinic researchers published in the Journal of Clinical Oncology.... Mayo Clinic researchers found that the number of HER2-positive breast cancers doubled....

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Number of HER2-positive Breast Cancers Double Under New Testing Guidelines
August 1, 2016
by Ines Martins, PhD