The third breast cancer cells, SK-BR3 resembles MCF7 and MDA-MB-468 with respect to acid-induced matriptase activation (Fig. 3D, lane 1), immunodepletion, and the elution of uncomplexed activated matriptase from the activated matriptase mAb beads (Fig. 3D, lanes 2 and 3). Here, ST14 is linked to breast carcinoma.