PIK3CA Mutations in HR+, HER2- Metastatic Breast Cancer

Uncovering PIK3CA mutations

Just as your HR and HER2 status inform your doctor whether certain proteins fuel your cancer, your PIK3CA mutation status tells your doctor whether a common gene mutation may be contributing to the growth of your cancer. If you have a PIK3CA mutation, that means you have an abnormal (or mutated) PIK3CA gene, which can create proteins that may cause cancer cells to grow and spread. PIK3CA mutations are the most common type of mutation in HR+, HER2- metastatic breast cancer.


How common are PIK3CA mutations?

breast cancer statistic

If you test positive for a PIK3CA mutation and progressed on or after hormone therapy, you and your doctor can consider PIQRAY® (alpelisib) tablets.

PIK3CA mutation testing

To determine your PIK3CA mutation status, your doctor will test your breast cancer for an abnormal PIK3CA gene. PIK3CA mutations are sporadic, meaning they occur at random and aren’t passed down from parent to child. PIK3CA mutations can only be detected through a specific genomic test ordered by your doctor, so even if you’ve had genetic testing done before, ask about getting tested specifically for a PIK3CA mutation.


Your doctor will send a tissue or blood sample for testing. If you’ve had a biopsy done before, ask your doctor if your tissue is still viable for PIK3CA gene mutation testing.


If no mutation is found in the blood sample, ask your doctor to test your tissue.

Sporadic mutations vs. inherited mutations