Tissue endosialin expression was assessed on tumor biopsy samples (paired sampling) obtained either at screening or from archival blocks and between Days 22 and 28 of Cycle 1 in a subset of 30 patients. PDGFR-β tumor tissue expression was assessed at screening only.
Formalin-fixed-paraffin-embedded slides were prepared and assessed for endosialin and PDGFR-β expression by immunohistochemistry using the previously described rat anti-human endosialin 9G5 monoclonal antibody [30 (link)] or clone 28E1 (Cell Signaling, Danvers, MA, USA) for PDGFR-β [20 (link), 26 ] by Quintiles Laboratories Americas (Marietta, GA and Westmont, IL). Expression was reported as +1, +2, or +3 as assessed by a single board certified pathologist.
Baseline serum samples were collected for evaluation of soluble endosialin using electrochemiluminescent assays performed by Frontage Laboratories, Inc. (Exton, PA) using endosialin-specific monoclonal antibodies [30 (link)].
Formalin-fixed-paraffin-embedded slides were prepared and assessed for endosialin and PDGFR-β expression by immunohistochemistry using the previously described rat anti-human endosialin 9G5 monoclonal antibody [30 (link)] or clone 28E1 (Cell Signaling, Danvers, MA, USA) for PDGFR-β [20 (link), 26 ] by Quintiles Laboratories Americas (Marietta, GA and Westmont, IL). Expression was reported as +1, +2, or +3 as assessed by a single board certified pathologist.
Baseline serum samples were collected for evaluation of soluble endosialin using electrochemiluminescent assays performed by Frontage Laboratories, Inc. (Exton, PA) using endosialin-specific monoclonal antibodies [30 (link)].
