Figure 2C shows the proliferation rate of PIG-1 melanocytes in comparison to A375 melanoma cells. We confirmed that tumor cells exhibited higher intracellular levels of ROS than their non-tumor counterpart in this melanoma/melanocyte model (Figures 1E and 1F). No significant differences in the levels of ROS and in the proliferation rate (Figure S2) were observed between non treated and heat-inactivated catalase treated cells in the melanoma model. Here, CAT is linked to melanoma.