BRAF and neoplasm: We modeled the impact of the fitness of the BRAF-variant-containing subclones and the variant acquisition times on the tumor fraction using:1\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$x\left( t \right) = \frac{{e^{st}}}{{e^t + e^{st}}}$$\end{document}xt=estet+estwhere s is the relative rates of growth between the BRAF-variant subclones compared to the (wild-type) host tumor25.