SOX antibodies have become useful markers of SCLC in these PNDs, most notably in LEMS, where SOX1 and SOX2 antibodies have been found in 64–78% of patients with SCLC and LEMS compared with only 0–5% in non-tumour LEMS patients (Titulaer et al., 2009; Sabater et al., 2008). This evidence concerns the gene SOX2 and Lambert-Eaton myasthenic syndrome.