Expression analysis by qrt-PCR in tumor cells isolates showed a strong reduction of p19Arf mRNA versus Lgl1 cKO Ink4a/Arf WT and Ink4a/Arf+/− cells, suggesting that the WT allele of p19Arf is not expressed in the tumor (Supplementary Fig. 5b). The gene discussed is LLGL1; the disease is neoplasm.