Abraxane Study (Phase 2 study)

>>Approximately 30% of all metastatic breast cancer patients are HER2-positive.

If the above is true, and 30% of all breast cancer patients are HER2 +++, wouldn't that mean that their is no difference in the rate of metastasis of HER2 and non HER2 cancers? I thought there was a higher incidence.
Janet/FL