SDHB and gastrointestinal stromal tumor: INT2GRATE|HPPGL analysis of cases with SDHA VUS (n = 40) showed that four patients had a personal history of PGL/PCC ± associated GIST, none had a family history of PGL/PCC, none carried a somatic inactivating allele, none had any IHC findings suggestive of SDHA/SDHB loss of expression, and all had a wild-type KIT or PDGFRA status (Table 5).