Highly aggressive behavior of malignant rhabdoid tumor: a special reference to SMARCB1/INI1 gene alterations using molecular genetic analysis including quantitative real-time PCR
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SMARCB1/INI1, which negatively regulates cell cycle progression from G0/G1 into the S-phase via the p16INK4a-RB-E2F pathway, has been reported to be inactivated homozygously by deletion and/or mutations in malignant rhabdoid tumor (MRT). In the current study, we investigated the alteration of the SMARCB1/INI1 gene using simple methods, and its gene product at the protein level. Moreover, we investigated the status of hyperphosphorylation in RB protein, known as a key cell cycle molecule.
Three cell lines and 11 formalin-fixed, paraffin-embedded specimens of MRT were investigated. SMARCB1/INI1 gene alteration was analyzed with simple methods as a quantitative real-time PCR and direct sequencing method. Furthermore, SMARCB1/INI1 and RB protein were immunohistochemically evaluated.
In 12 of 14 cases, we detected genetic alterations comprised of nine (including three cell lines) homozygous deletions and three mutations, which can induce abnormal expression of gene products. At the protein level, SMARCB1/INI1 immunohistochemical expressions were not detected in any cases. Twelve out of 14 cases showed high-level (+5) expression of tRB (both hyperphosphorylated and underphosphorylated RB), combined with low-level (+1) expression of uRB (underphosphorylated RB), indicating a high rate of hyperphosphorylation.
We could analyze the SMARCB1/INI1 gene alteration with simple methods, and SMARCB1/INI1 gene alteration was found in 12 of 14 cases. Especially, quantitative real-time PCR was a convenient and accurate method. In addition, a high rate of hyperphosphorylation of RB gene was recognized. These results suggest that the clinically aggressive character of MRT is caused by the inactivation of the SMARCB1/INI1 gene.
KeywordsMalignant rhabdoid tumor SMARCB1/INI1 RB Quantitative real-time PCR Immunohistochemistry
Malignant rhabdoid tumor
Extrarenal malignant rhabdoid tumor
Malignant rhabdoid tumor of the kidney
Both hyperphosphorylated and underphosphorylated RB
Threshold cycle numbers
Gene dosage ratio
This study was supported by a Grant-in-Aid for Scientific Research (C) (no. 18590332) from the Japan Society for the Promotion of Science, Tokyo, Japan. English used in this manuscript was revised by KN International (http://www.kninter.com/).
- Berggren P, Kumar R, Sakano S, Hemminki L, Wada T, Steineck G, Adolfsson J, Larsson P, Norming U, Wijkstrom H, Hemminki K (2003) Detecting homozygous deletions in the CDKN2A(p16(INK4a))/ARF(p14(ARF)) gene in urinary bladder cancer using real-time quantitative PCR. Clin Cancer Res 9:235–242PubMedGoogle Scholar
- Bonnin JM, Rubinstein LJ, Palmer NF, Beckwith JB (1984) The association of embryonal tumors originating in the kidney and in the brain. A report of seven cases. Cancer 54:2137–2146Google Scholar
- Izumi T, Oda Y, Hasegawa T, Nakanishi Y, Iwasaki H, Sonobe H, Goto H, Kusakabe H, Takahira T, Kobayashi C, Kawaguchi KI, Saito T, Yamamoto H, Tamiya S, Iwamoto Y, Tsuneyoshi M (2006) Prognostic significance of dysadherin expression in epithelioid sarcoma and its diagnostic utility in distinguishing epithelioid sarcoma from malignant rhabdoid tumor. Mod Pathol 19:820–831PubMedGoogle Scholar
- Kinoshita Y, Shiratsuchi H, Tamiya S, Oshiro Y, Hachitanda Y, Oda Y, Suita S, Tsuneyoshi M (2001a) Mutations of the p53 gene in malignant rhabdoid tumors of soft tissue and the kidney: immunohistochemical and DNA direct sequencing analysis. J Cancer Res Clin Oncol 127:351–358PubMedCrossRefGoogle Scholar
- Labuhn M, Jones G, Speel EJ, Maier D, Zweifel C, Gratzl O, Van Meir EG, Hegi ME, Merlo A (2001) Quantitative real-time PCR does not show selective targeting of p14(ARF) but concomitant inactivation of both p16(INK4A) and p14(ARF) in 105 human primary gliomas. Oncogene 20:1103–1109PubMedCrossRefGoogle Scholar
- Polsky D, Mastorides S, Kim D, Dudas M, Leon L, Leung D, Woodruff JM, Brennan MF, Osman I, Cordon-Cardo C (2006) Altered patterns of RB expression define groups of soft tissue sarcoma patients with distinct biological and clinical behavior. Histol Histopathol 7:743–752Google Scholar
- Schofield D (2002) Extrarenal rhabdoid tumour. In: Fletcher CDM, Unni KK, Mertens F (eds) WHO classification of tumours, pathology and genetics of tumours of soft tissue and bone. IARG Press, Lyon, France, pp 219–220Google Scholar
- Shiratsuchi H, Saito T, Sakamoto A, Itakura E, Tamiya S, Oshiro Y, Oda Y, Toh S, Komiyama S, Tsuneyoshi M (2002) Mutation analysis of human cytokeratin 8 gene in malignant rhabdoid tumor: a possible association with intracytoplasmic inclusion body formation. Mod Pathol 15:146–153PubMedCrossRefGoogle Scholar
- Sigauke E, Rakheja D, Maddox DL, Hladik CL, White CL, Timmons CF, Raisanen J (2006) Absence of expression of SMARCB1/INI1 in malignant rhabdoid tumors of the central nervous system, kidneys and soft tissue: an immunohistochemical study with implications for diagnosis. Mod Pathol 19:717–725PubMedCrossRefGoogle Scholar