MC1R and colon carcinoma: The macrophage/monocyte line THP-1 showed the same levels of α-MSH binding as LPS- or cytokine stimulated monocytes (Figure 5A), confirming the MC1R expression in this line (Rajora et al, 1996), while an ovarian and a colon carcinoma (OV3507, SW480) included as controls only bound low to insignificant levels of α-MSH.