These examples suggest that certain GPCRs are selectively overexpressed in specific cancer types, suggesting that different types of cancer may each possess a unique “GPCR-ome.” Certain GPCRs (e.g., CD97 and GPR56) are expressed in multiple cancer types, but also are widely expressed in normal tissue and cells (e.g., Uhlén et al., 2015, corresponding data for each GPCR hosted at proteinatlas.org). Here, FZD4 is linked to cancer.