Chromosomal imbalances detected by comparative genomic hybridisation in atypical teratoid/rhabdoid tumours

Abstract

Introduction: Atypical teratoid/rhabdoid tumours (AT/RT) are highly malignant embryonal tumours of the brain composed of rhabdoid cells. Inactivating mutations of the hSNF5/INI-1 gene located in the chromosomal region 22q11.2 are regarded as a crucial step in their molecular pathogenesis. Apart from monosomy or deletions of chromosome 22 not much data exists on additional chromosomal aberrations.

Methods: We investigated seven primary AT/RT by comparative genomic hybridisation (CGH) and found DNA copy number changes in each case.

Results: These consisted of loss of 22q in 7 out of 7 (100%) and loss of 19 in 3 out of 7 (43%) patients. In 4/7 AT/RT (57%), loss of chromosome 22q was the sole aberration whereas one patient showed additional losses of 16p, 17p and 20q.

Conclusions: Our CGH data suggest that apart from monosomy 22 additional genetic pathways may seem feasible for a subset of AT/RT that is yet to be defined. Furthermore, this study also emphasises the potential practical value of loss of chromosome 22 as a diagnostic marker for AT/RT.