Lastly, our current understanding linking NRG1 expression along with other EGFR activation biomarkers will help guide the future development of anti-ErbB3 mAbs such as KTN3379 in combination with anti-EGFR mAbs such as cetuximab in HNSCC and other tumor types where both EGFR and ErbB3 signaling play a role together. Here, EGFR is linked to head and neck squamous cell carcinoma.