PRSS contributes to cetuximab resistance in colorectal cancer

Tan, Zhaoli; Gao, Lihua; Wang, Yan; Yin, Huihui; Xi, Yongyi; Wu, Xiaojie; Shao, Yong; Qiu, Weiyi; Du, Peng; Shen, Wenlong; Fu, Ling; Jia, Ru; Zhao, Chuanhua; Zhang, Yun; Zhao, Zhihu; Sun, Zhiwei; Chen, Hongxing; Hu, Xianwen; Xu, Jianming; Wang, Youliang

As our results showed that the band of cleavage produced by PRSS1, which may not be effective, can also be captured by goat anti-human immunoglobulin G (IgG) (Fig. 3A) . We doubted that a traditional ELISA, which involves the use of a horseradish peroxidase (HRP)-conjugated rabbit or goat anti-human IgG as the detection antibody, could thoroughly uncover the pharmacokinetic profile of cetuximab in patients with solid tumors expressing EGFR. To test the pharmacokinetic profile of cetuximab, we used a goat antimouse IgG antibody, which captures only the heavy and light chains of cetuximab, and a goat anti-human IgG antibody as the detection antibody. Immunoblotting showed that using the goat anti-mouse IgG antibody as the detection antibody yielded a more accurate pharmacokinetic profile of cetuximab ( fig. S2 , B and C).