Cellular uptake of [<sup>123</sup>I]3 and [<sup>123</sup>I]4 was evaluated in human cells with distinct COX-2 and 5-LO expression: U87 glioblastoma, HT-29 colorectal carcinoma cells, THP-1 monocytes (MC) and macrophages. Here, PTGS2 is linked to colorectal carcinoma.