Sotorasib Is Not Effective in a KRAS-Mutated Patient With Brain Metastases From Lung Adenocarcinoma due to Multiple Gene Co-Mutations.

A 60-year-old man diagnosed with lung adenocarcinoma underwent standard left lower lobectomy. However, he developed brain metastasis 10 months later, and the metastatic lesion was resected surgically. At that time, the KRAS G12C mutation was detected in the metastatic tissue by the Oncomine Dx Target Test. After 16 months, liver metastases appeared, and treatment with sotorasib was initiated. Unexpectedly, however, Sotorasib was ineffective, and the disease progressed. Cancer Genome Profiling (CGP) Test revealed that mutations of and were already present in the patient's primary tumour, resulting in the initial resistance to standard targeted therapy.