SDHB and cancer: We would suggest that if an SDHA PGV is identified in an individual with cancer but in an off-tumour setting, for example, through WGS or extended gene panel testing, that the PGV is reported but coupled with a recommendation that SDH immunohistochemistry (IHC) is performed and the finding considered to be a non-actionable secondary finding unless there is immunohistochemical evidence of SDHB/SDHA protein loss or a family history of SDHA-associated tumours (table 2).