BRAF and colorectal neoplasm: Furthermore, single agent WX-554 induced tumour growth delay at 2 mg/kg in HCT116 colorectal tumour xenograft models, consistent with previous unpublished studies using WX-554 and published studies using other MEK inhibitors that reported tumour growth delay or stasis in vivo, with increased sensitivity in BRAF or RAS mutant cells and tumours [3–5, 25].