ASIC1 and pheochromocytoma: For example, ENaC alpha and ASIC1/2 were both found to be expressed in human pheochromocytoma wildtype cells and mutant cells with a knockdown of succinate dehydrogenase subunit B (SDHB), but there were significantly lower levels of the cleaved 60 kDa form of ENaC in SDHB KD cells [50].