However, in clinical trials involving patients with renal cell carcinoma (14 patients) [18] and metastatic colorectal cancer (12 patients) [27], no correlation was observed between uptake of tracer and intratumoural VEGF expression level, measured using either enzyme-linked immunosorbent assays (ELISAs), in situ hybridisation (ISH) or immunohistochemistry (IHC). This evidence concerns the gene VEGFA and metastatic colorectal cancer.