Indeed, further subgroup analysis of the LUX‐Head and Neck 1 trial identified biomarkers (HPV‐negative, EGFR‐amplified, low HER3 expression, and high PTEN expression) that could predict clinical outcomes with afatinib versus methotrexate in R/M HNSCC. Here, ERBB3 is linked to head and neck squamous cell carcinoma.