Recent studies demonstrate the role of the tumor microenvironment in tumor progression. However， strategies used to overcome the malignant phenotypes of cancer cells modulated by the microenvironment have not been thoroughly explored. In this study， we evaluated the therapeutic efficacy of a newly developed monoclonal antibody targeting microfibril associated protein 5 (MFAP5)， which is secreted predominately by CAFs， in ovarian and pancreatic cancer models.