Further screening of these patients revealed four cases with tumors: three young females had ovarian teratomas (two were anti-NMDAR positive; one was positive for both anti-NMDAR and mGluR5), and one 45-year-old male had small cell lung cancer (positive for anti-GABABR, GAD65, SOX1, and Ma2). Here, PNMA2 is linked to ovarian teratoma.