SDHB

Succinate dehydrogenase B (SDHB) is a protein subunit that forms the succinate dehydrogenase (SDH) complex with SDHA, SDHC, and SDHD. SDH mainly exists in the mitochondrial inner membrane, and it is currently the only catalytic enzyme that participates in both the tricarboxylic acid cycle and the electron transport chain, which plays a crucial role in energy metabolism. Some research has found that SDH has tumor inhibition effect, but the mutation or inactivation of SDHB will result in SDH dysfunction, which can induce the occurrence of SDH deficient tumors, including pheochromocytoma, paraganglioma, gastrointestinal stromal tumors, renal cancer, etc. This may be due to the dysfunction of mitochondria leading to DNA damage, metabolic disorder, and oxidative stress. Therefore, the negative expression of SDHB is considered as one of the diagnostic indicators for SDH deficient tumors, which suggests poor prognosis of patients. In addition, some scholars believe that the absence of SDHB may promote cell cycle progression to accelerate the proliferation of colorectal cancer cells.