Serum Nectin-4 and disease progression. Nectin-4, CEA and CA15.3 serum levels were determined during disease progression of a patient with a ductal carcinoma. The three markers were not detected at the time of diagnosis (white bar). During the progression of the disease, Nectin-4 serum levels increased to reach 402 pM. Grey, detection of pulmonary metastasis 32 months post-diagnosis; black, detection of brain metastasis 39 months post-diagnosis. Ordinates represent pM for Nectin-4 and International Units for CEA and CA15.3.