POMC and Burkitt lymphoma: Thus, the decrease in downstream steroidogenesis enzymes (CYP11B1, CYP11B2 and CYP17A1-17,20 lyase) activity in BL patients could explain the increased amplitude of response to ACTH of the five steroid precursors studied: progesterone, 17OHP, 11-deoxycorticosterone, corticosterone and 11-deoxycortisol.