TNF and melanoma: To investigate whether the lower sensitivity of UACC62P cells to mitotic inhibitors might be attributed to their more differentiated state compared with UACC62R cells, we treated both UACC62P and M229P cells with tumor necrosis factor α (TNFα) which has been shown to induce de-differentiation of melanoma cells (25, 26), and assessed the impact on sensitivity to a panel of mitotic inhibitors (Figure S5).