NRAS and neoplasm: Cells of various kinds of benign, static neoplasms in vivo show markers of senescence, for example, in melanocytic nevi, which generally carry activating v-raf murine sarcoma viral oncogene homolog B1 (BRAF) or neuroblastoma RAS viral oncogene homolog (NRAS) mutations (Gray-Schopfer et al., 2006; Michaloglou et al., 2005).