Plasmin [16,17], proprotein convertase PC5A [3], cathepsin E [3], MBP [3,18], presenilin/gamma-secretase [4,19,20], beta-secretase 1/BACE1 [21,22], metalloproteinases [4,23,24] and neuropsin [25,26] have been identified as L1-cleaving proteases in neural and tumor cells. Here, BACE1 is linked to neoplasm.