Activatable Antibodies for Tissue Microarrays

Example 11

The present Example describes using activatable antibodies to detect expression and/or activation in tissue microarrays (TMAs). The anti-Jagged antibody 4D11 was used with a non-small cell lung cancer (NSCLC) TMA and a breast cancer (BC) TMA. Most of the NSCLC and BC patient tumor samples were positive for Jagged expression. The same NSCLC and BC TMAs were contacted with the activatable anti-Jagged antibody referred to herein as 5342-1204-4D11. 97% of NSCLC and 100% of BC patient tumor samples were positive for binding and activation of 5342-1204-4D11 activatable anti-Jagged antibody. Furthermore, more than 80% of the tumor samples were characterized by a high activation rate (++or +++) as shown in FIG. 21. The same NSCLC and BC TMAs were contacted with the A11 antibody, which binds to the protease MT-SP1. 77% of the NSCLC and 98% of the BC patient tumor samples were positive for MT-SP1 activity. 8 NSCLC tumors lacked MT-SP1 activity, but demonstrated binding and activation of the 5342-1204-4D11 activatable anti-Jagged antibody, which suggests the participation of proteases in the activation of the 5342-1204-4D11 activatable anti-Jagged antibody.