[Interphase cytogenetics--a new technique for analysis of acquired genetic changes in tumor cells]

Newer genetic investigations of solid tumours by means of in situ hybridization (ISH) is reviewed. In situ hybridization, ISH, is a relatively new molecular biological method which can be used as a supplement to analysis of chromosome aberrations in tumour cells. Labelled DNA or RNA sequences (probes) are bound to specific sequences on cell chromosomes. After hybridization, the complementary sequences of the probe can be visualized and observed in a microscope. In contrast to classical cytogenetics where the chromosomes are studied in the mitosis, ISH can also be carried out on non-mitotic cells. The term "interphase cytogenetics" refers to this application of ISH, which can demonstrate the distribution of cells with different genotype without previous cell culturing. Interphase cytogenetics has been used for the analysis of several different tumour types where it gives fast and reliable information about specific cytogenetic aberrations in tumour cells. It is to be anticipated that this laboratory technique will be employed increasingly in the diagnosis and follow-up of certain malignancies.