Altered tumor suppressor pathways in MN1-TEL–positive tumors. (A) Expression of tumor suppressors in MN1-TEL–positive tumors. Western blot of 6 tumor lysates with anti-p19^Arf or -p16Ink4a antibody. Gapdh was used as loading controls. Control: normal thymocytes. (B) Lack of p53 up-regulation induced by γ-irradiation in MN1-TEL–positive tumors showing p19^Arf up-regulation. Cells were harvested 3 hours after 5 Gy γ-irradiation and subjected to Western blot analysis with anti-p53 antibody. Gapdh was used as loading controls. IR indicates γ-irradiation; T, tumors. Control: normal thymocytes. Representative data are shown. (C) Down-regulation of pRb mRNA in MN1-TEL–positive tumors. Quantitative RT-PCR results are shown. C indicates control thymocytes (n = 5); T, tumors (n = 5).