Indeed, patients >65 years with a history of ILD had a significantly high recurrence rate.[7] Other possible risk factors include lung metastases, high baseline KL-6, high smoking index, squamous-cell carcinoma, and ≥2 prior chemotherapy regimens (vs ≤1).[3,7] The patient reported here had a low level of lung fibrosis before cetuximab, but no ILD was diagnosed, but he was > 65 years old, had lung metastases, and had a history of heavy smoking. Here, MUC1 is linked to squamous cell carcinoma.