Semi-Automated FISH analysis of cells on slides Automated Post-Hybridization in a FISH protocol of leukaemia cells from blood with the Tecan GenePaint system

Fluorescence In situ hybridization (FISH) is a technique that can be used for the analysis of genomic aberrations in tumor cells. The resolution level of FISH is by far better than chromosome banding which is also widely used for the study of chromosome aberrations in cancer. In addition to the improved resolution FISH allows for the analysis of genomic aberrations not only on metaphase chromosomes but also in interphase cells (“interphase cytogenetics”). This improves the sensitivity for the detection of genomic aberrations in many tumors. In fact, in some leukaemias the incidence of chromosomal aberrations is almost twice as high as compared to chromosome banding. The reason is that, for FISH no dividing cells are needed, i.e. there is no need for short term in-vitro culture for cells to obtain metaphase spreads. This is a key advantage in tumors with a low in-vitro proliferative index such as some leukaemias and lymphomas. The principle of FISH for the study of genomic aberrations is the evaluation of the number and localization of fluorescence signals in the cell nucleus or on metaphase chromosomes. Aberrant numbers or local distributions indicate numerical or structural chromosomal aberrations.