The developmental and oncogenic roles of MYC proteins are well established, but the transcriptional targets mediating their functions remain elusive. Using small interfering RNA-mediated knockdown in breast and cervix carcinoma cell lines, which overexpress c-MYC, we show that c-MYC independently controls metabolism and cell proliferation, and can, depending on the cells, promote or inhibit migration. We identified new c-MYC target genes in these cell lines, and show that selective regulation of some targets correlates with the phenotypic responses of these different cell lines to c-MYC depletion. Notably, we show that a positive regulation of the WNT signalling pathway contributes to c-MYC pro-mitogenic effects in breast and cervix carcinoma cells. We also show that repression of CCL5/RANTES accounts for c-MYC anti-migratory effects in specific breast cancer cells. Our combined genomic and phenotypic analysis indicates that c-MYC functions are cellular-context-dependent and that selectively regulated genes are responsible for its differential properties.