It is assumed that the latter is further influenced by the specific SDHx subunit mutation and type of mutation, for example, missense versus truncating mutations.25, 24–26 Combining the results from our cohort with the data analysis of published datasets, no significant difference in mean MGMT methylation levels in SDH-deficient GIST with different underlying SDHx subunit gene mutations or SDHC epimutations, was identified. Here, SDHC is linked to gastrointestinal stromal tumor.