SDHB and kidney cancer: Notably, basal respiration, maximal respiratory capacity, and ATP-coupled production are severely impaired in several SDHx-deficient cancer cell models, including SDHB knockout (KO) MDA231 human breast cancer cells [18], SDHD KO HEK293 human embryonic kidney cells [19], SDHB mutant UOK269 human kidney cancer cells [20,21], Sdha KO and Sdhb KO RAW 264.7 mouse macrophage cells [22], and Sdhb KO mouse epithelial kidney cells [23].