SDHD and neoplasm: Consistent with this notion, multiparameter DNA flow cytometry analysis of SDHD-related tumours indicates that chief cells are the neoplastic component of paragangliomas [23]: utilizing S-100 labelling as a selective marker for the sustentacular fraction, this study showed that S-100-labelled cells are diploid, and show retention of the wild-type allele, while loss of the wild-type allele was seen in the S-100-negative fraction.