A transcriptomic analysis of 76 inherited and sporadic PPGLs identified 2 tumour clusters, one including SDHB, SDHD and VHL-mutated tumours (pseudohypoxic signalling cluster), and one comprising RET and NF1-mutated (kinase signalling cluster) tumours (Dahia et al. 2005). Here, SDHB is linked to neoplasm.