AVP and neoplasm: In a recent study using Drosophila melanogaster as a conserved tumor model, isoform F of ion transport peptide (ITPF) was found to be secreted by gut tumor cells and acts as an antidiuretic hormone targeting the tachykinin receptor (TkR99D) in Malpighian tubules leading to compromised renal function that results in the accumulation of excess fluid (32).