Combined RB1/p130 ablation using the same murine model as in the current studies was not sufficient to induce lung tumors.11 In addition, combined RB1/p107 loss led to an increased incidence of NSCL tumors that lacked the aggressive metastatic phenotype of RB1/p16-deficient tumors and was not sufficient to induce SCLC.11 Taken together these studies indicate that p16 effects in RB1-deficient cells cannot be solely explained by loss of RB1 family function. The gene discussed is RBL1; the disease is small cell lung carcinoma.