Fluorescence in situ Hybridization Useful in Clinical Analysis to Search Quickly for Deletion of the Chromosome 22 for Diagnosis of Atypical Teratoid/rhabdoid Tumor

• Published in: Japanese Journal of National Medical Services Vol. 61; no. 7; pp. 466 - 471
• Main Authors: NAKAJIMA, Kouhei, POOH, Kyonhon, HIRABE, Saburo, IWAI, Tsuyako, ITO, Michinori, NAKAGAWA, Yoshinobu, YOKOTA, Ichiro, SONE, Michiko
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of National Medical Services 20.07.2007
• Subjects: 22g11.2; atypical teratoid/rhabdoid tumor; FISH; SMARCB1; SNF5/INI1
• ISSN: 0021-1699; 1884-8729
• DOI: 10.11261/iryo1946.61.466

Atypical teratoid/rhabdoid tumors (AT/RT) among the central nervous system tumors are highly malignant embryonal tumors. Mutation in the SMARCB1 tumor suppressor gene located in the long arm of chromosome 22 band q11.2 (22q11.2) is regarded as a crucial step of AT/RT in the molecular pathogenesis. Analysis of molecular genetics of the SMARCB1 gene is important in tumor classification of AT/RT, but the identifying of mutations in the SMARCB1 gene is difficult in routine clinical analysis. Therefore commercial probes (DiGeorge/VCFS region probe: CYTOCELL, LSI BCR/ABL probe: VYSIS) were used for the search of the 22q11.2 region included in the SMARCB1 gene, TUPLE1 locus and BCR locus as proximal markers. A telomere probe of chromosome 22 was used as a distal marker. Using frozen specimens, we investigated four central nervous system tumors (three AT/RT, one choroid plexus carcinoma) by FISH (fluorescence in situ hybridization) and did chromosome analyses. The deletions of the 22q11.2 region were observed quickly in all four cases by FISH. Four of two cases were confirmed to have terminal deletions of the 22q11.2, one case was 22 monosomy as the only cytogenetic abnormality by chromosome analyses. The result of FISH suggested that loss of the SMARCB1 gene region. It was concluded that using FISH on frozen specimens was useful as a clinical analysis to quickly search for deletion of the SMARCB1 gene region for diagnosis of AT/RT.