IGF1 and cancer: The insulin-like growth factor (IGF) signalling axis plays a role in carcinogenesis and is associated with cancer progression, prognosis, and treatment resistance.1 Consequently, therapeutic targeting of the IGF axis has been investigated in various human cancers, with early strategies targeting the IGF type 1 receptor (IGF-1R) using anti-IGF-1R monoclonal antibodies (mAbs) and IGF-1R tyrosine kinase inhibitors (TKIs).2 So far, there has been limited success with these agents, although this may reflect the lack of validated predictive biomarkers to allow patient enrichment.3