One patient (a 53-year-old man) with advanced NSCLC developed grade 3 ALT elevation, grade 3 AST elevation, and grade 1 pneumonitis (onset, day 42 for each); after the discontinuation of pembrolizumab treatment, he developed grade 3 hyponatremia (onset, day 56). The gene discussed is GPT; the disease is Hyponatremia.