A 52-year-old women with non-small cell lung cancer presented after five cycles of treatment with atezolizumab for their non-small cell lung cancer with DKA. The blood glucose was 332 mg/dL (18.4 mmol/L), Hb1Ac was 7.9%, with an elevated anion gap, bicarbonate was 9.9 mmol/L, anion gap of 24 mmol/L, elevated serum B-hydroxybutyrate of 5.91 mmol/L, and pH of 6.9. They were treated with a bolus of insulin and discharged on subcutaneous insulin aspart and insulin glargine. The gene discussed is INS; the disease is non-small cell lung carcinoma.