I tend not to use a companion diagnostic test because I want more information with a wider panel. The tumor tests I often use are FoundationOne CDx, Caris Molecular Intelligence, and Tempus. I use Tempus because their financial aid is very generous and almost all of my patients qualify to be tested for less than $100. For germline genetic testing, Invitae, Myriad, and Color are also options. Invitae and Color are about $250 out of pocket without insurance. Many academic centers have their own gene panels as well.
How far have we come in identifying biomarkers in MBC?
Targeted treatment for breast cancer has advanced significantly since doing my PhD research in cancer biology about 15 years ago. Of course, targeted therapies for ER-positive and HER2-amplified cancers were available at that point, but many more have been developed. The most significant advance has been the development of efficient and affordable genome sequencing, which has led to these large panels and identification of therapeutic targets. We’ve also expanded our knowledge of genetic predispositions for breast cancer beyond BRCA1 and BRCA2, which not only allows us to preemptively advise patients and their families about cancer risks and recommendations for cancer screening, but also to select a therapy to target a cancer’s DNA repair deficits.
I feel that we are in an exciting discovery phase in oncology. We currently rely on biomarkers to manage MBC and will continue to refine our strategies and develop more effective drug therapies as we identify more oncogenic drivers, tumor-specific proteins, and cancer cell vulnerabilities.