Accordingly, K-Ras/NICD tumors displayed a high desmoplastic reaction, as revealed by histologic analysis and highlighted by immunoreactivity for vimentin (VIM) in the stromal fibroblasts and myofibroblasts as well as strong Sirius Red staining of the collagen fibers within the tumor tissue (Fig. 4a). The gene discussed is KRAS; the disease is neoplasm.