The aim of this work was to identify bioactive molecules that (1) efficiently and selectively inhibit the MYC:MAX interaction in vitro and in cells, that (2) bind MYC directly with high affinity, that (3) inhibit MYC-dependent tumor cell growth with high efficacy, that (4) do not affect MYC expression, and that (5) are active in vivo. This evidence concerns the gene MYC and neoplasm.