Hu antigen C HUC ELAV-like protein 3 paraneoplastic cerebellar degeneration-associated antigen hu-antigen C ELAV (embryonic lethal, abnormal vision, Drosophila)-like 3 (Hu antigen C) ELAV like neuron-specific RNA binding protein 3 HUCL paraneoplastic limbic encephalitis antigen 21 PLE21