Detecting Immune Response to Therapies Targeting PDL1 and BRAF by Using Ferumoxytol MRI and Macrin in Anaplastic Thyroid Cancer

Background Anaplastic thyroid cancer (ATC) is aggressive with a poor prognosis, partly because of the immunosuppressive microenvironment created by tumor-associated macrophages (TAMs). Purpose To understand the relationship between TAM infiltration, tumor vascularization, and corresponding drug delivery by using ferumoxytol-enhanced MRI and macrin in an ATC mouse model. Materials and Methods ATC tumors were generated in 6-8-week-old female B6129SF1/J mice through intrathyroid injection to model orthotopic tumors, or intravenously to model hematogenous metastasis, and prospectively enrolled randomly into treatment cohorts (