What biomarker tests should I ask for with breast cancer

I'll help explain the key biomarker tests recommended for breast cancer patients according to major guidelines.

According to the NCCN Breast Cancer Guidelines (2023), there are three essential biomarker tests that should be performed on all newly diagnosed invasive breast cancers:

1. Hormone Receptor Status:

• Estrogen Receptor (ER)
• Progesterone Receptor (PR)

1. HER2 Status Testing

2. Ki-67 (in some cases)

The American Society of Clinical Oncology (ASCO) Guidelines specifically recommend:

• Initial testing should include both immunohistochemistry (IHC) for ER/PR
• HER2 testing using either IHC or in situ hybridization (ISH) methods
• Retesting may be needed if you have metastatic disease or recurrence

The National Cancer Institute (NCI) adds that additional biomarker testing may be recommended in specific situations:

• Genomic tests like Oncotype DX, MammaPrint, or EndoPredict for early-stage hormone receptor-positive cancers to help guide treatment decisions
• PD-L1 testing for triple-negative breast cancer patients considering immunotherapy

Important notes:

1. These tests should be done before starting treatment as they guide therapy choices
2. Results should be available within 2 weeks of biopsy
3. Always discuss the complete testing plan with your oncologist as individual needs may vary

I recommend asking your healthcare team:

• Have all three standard biomarkers (ER, PR, HER2) been tested?
• Would genomic testing be appropriate in my case?
• Are there any additional biomarker tests specific to my situation?

Remember: This information is meant to help you have informed discussions with your healthcare team, who will determine the most appropriate tests for your specific situation.