In prior work, we showed that ex-vivo lentiviral transduction with oncogenic Kras (G12v) of Cdkn2a (p16p19)-deficient myofiber-associated (MFA) cells, isolated by fluorescence activated cell sorting (FACS) from muscle tissue of Cdkn2a-/- mice, drives rapid sarcoma formation upon transplantation of these cells into the muscle of immunocompromised mice (Hettmer et al., 2011) (Figure 1—figure supplement 1). This evidence concerns the gene KRAS and sarcoma.