MAOA and neoplasm: demonstrated dramatic tumor-suppressive effects of the MAOI antidepressants phenelzine, clorgyline, and moclobemide, which represented three classes of MAOIs, varying in the reversibility of the drug’s effects (reversible vs irreversible) and the selectivity for the serotonin-degrading MAO-A isoform over MAO-B (selective vs nonselective) (5).