SDHC and gastrointestinal stromal tumor: In this case, tumors with somatic PVs in these genes or epigenetic alterations that result in a similar phenotype are also of interest, for example SDHC promoter methylation in PPGL and gastrointestinal stromal tumors causing loss of SDHC expression and increased succinate levels (Killian et al. 2014, Richter et al. 2016).