A hippocampal protein associated with paraneoplastic neurologic syndrome and small cell lung carcinoma.

A hippocampal 38 kd autoantigen recognized by an autoantibody from the serum of a patient with paraneoplastic limbic encephalitis (PLE) and small cell lung carcinoma (SCLC) was isolated by screening a human hippocampal cDNA library. The 1,991-nucleotide ple21 clone was obtained and the deduced 350-residue protein encoded by the ple21 cDNA clone was found to be highly homologous to the neuron-specific RNA recognition motifs (RRMs)-containing proteins. The homologies were confined to the RRMs and the RRM connecting region. The presence of RRM in the antigenic protein may be important in the pathogenesis of SCLC-associated paraneoplastic neurologic syndrome.