Eide et al. used sheep anti-mouse IgG antibody-coated superparamagnetic particles conjugated with several antibodies (9.2.27 anti-melanoma-associated antibody, Ep-1 IgG1 antibody, and 376.96 antibody) and found CTCs in only 1.6% (n = 328) of UM patients [60]. Here, PTGER1 is linked to melanoma.