SDHB and digestive system carcinoma: Accordingly, germline mutations in SDH genes resulting in impaired SDH activity have been found in several tumor types including pheochromocytoma, paraganglioma, gastrointestinal carcinoma, renal cell carcinoma, thyroid carcinoma, neuroblastoma, and breast cancer along with altered SDH epigenetic and post-translational mechanisms of regulation [22,23,27,28,29].