Genetic testing and immunohistochemistry for SDHB in phaeochromocytoma-paraganglioma syndromes: the South Australian experience

Aim and methods

a retrospective review of germline genetic testing (VHL, RET and succinate dehydrogenase subunit genes SDHB, SDHC and SDHD) and immunohistochemical staining for SDHB in tumour tissue (SDHB-IHC), in patients referred to the South Australian Familial Cancer Unit with an adrenal phaeochromocytoma (PC) and/or paraganglioma (PGL).

Results

between January 1999 and May 2011, 24 probands were referred to and assessed by our service. The clinical presentation and mutation pick up are presented in the table. Tumour tissue was available from 20 probands and SDHB-IHC was abnormal in all probands with an SDH mutation (5/5; 100%), 0/1 with a VHL mutation and 2/12 (16%) with no identified mutation (the 2 probands with abnormal SDHB-IHC both presented with familial head & neck PGL). Tissue was unavailable for testing in the remaining 4 patients; 3 with a RET mutation and a MEN2 phenotype; 1 with an SDHD mutation and familial head & neck PGL (SDH-IHC is pending in her affected sister). Table 1.

Table 1

Conclusion

our experience supports using SDHB-IHC as a tool to triage genetic testing in patients with PC or PGL.