FURIN and cancer: To address this hypothesis and determine if ADAM17 inhibition is dependent on ADAM17 expression by cancer cells, we generated tumors with human DLD1 CRC cells expressing functional mature ADAM17 and human LoVo CRC cells expressing immature, inactive ADAM17 due to a deficiency in the proprotein convertase furin required for the processing of pro-ADAM17 into active ADAM17 [34,35].