Fluorescent in situ hybridisation (FISH) characterisation of pericentromeric breakpoints on chromosome 5 in head and neck squamous cell carcinomas

Pericentromeric rearrangements, such as isochromosomes and whole-arm transl ocations, are frequently encountered in short-term cultures from head and n eck squamous cell carcinomas (HNSCC). To characterise further the localisat ion of the breakpoints in such rearrangements, metaphase cells from seven H NSCC known to carry structural rearrangements of the pericentromeric region of chromosome 5 were investigated using fluorescent in situ, hybridisation (FISH) techniques. With a whole chromosome painting probe it could be conf irmed that all chromosome 5 rearrangements identified at cytogenetic analys is contained chromosome 5 material. By using a centromere-specific alpha sa tellite probe it could be shown, however, that; cytogenetically identical d erivative chromosomes had different breakpoints. Thus, we conclude that the results of the present investigation add further support to the hypothesis that the essential outcome of near-centromeric chromosome rearrangements i s the creation of genomic imbalances, i.e. gain and/or loss of neoplasia-as sociated genes. (C) 1999 Elsevier Science Ltd. All rights reserved.