F2R and neoplasm: Several GPCRs are critical for cell proliferation and survival, and can be aberrantly expressed in cancer cells.3, 4 For example, PAR1 is overexpressed in invasive breast carcinomas5 or advanced-stage prostate cancer.6, 7 Likewise, the chemokine receptor CXCR4 has an important role in tumor metastasis and angiogenesis.3, 4 Moreover, the Wnt target gene, Lgr5, identified as a marker of intestinal stem cells, is implicated in mouse intestinal tumorigenesis8, 9 and its expression is also associated with poor clinical outcome in colorectal cancer.10