2049 advanced breast cancer cases were submitted to Foundation Medicine within a 22-month window for CGP. 
Foundation Medicine
We compared genomic alterations using comprehensive genomic profiling (CGP) of tumor tissue among very young women (< 30 years) and young women (30-39 years) compared to women ≥ 40 years at diagnosis.


 2049 advanced breast cancer cases were submitted to Foundation Medicine within a 22-month window for CGP.  Hybrid-capture based CGP was performed to evaluate all classes of genomic alterations. 
CGP
Hybrid-capture based CGP was performed to evaluate all classes of genomic alterations. 
Hybrid-capture based CGP
Tumor mutational burden was determined on at least 0.8 Mbp of sequenced DNA and microsatellite instability was determined on at least 95 loci. 
Tumor mutational burden
Tumor mutational burden was determined on at least 0.8 Mbp of sequenced DNA and microsatellite instability was determined on at least 95 loci. 
Microsatellite instability
Immunocyte PD-L1 expression was determined by immunohistochemistry.



Immunocyte PD-L1 expression