MOLECULAR CYTOGENETICS IN CANCER-RESEARCH AND CLINICAL ONCOLOGY - HEMATOLOGICAL MALIGNANCIES

Molecular cytogenetics by fluorescence in situ hybridization (FISH) an d comparative genomic hybridization (CGH) complements metaphase cytoge netics in the analysis of genetic changes in malignancy. By FISH, defi ned numerical and structural aberrations can be detected even in fixed interphase cells. Thus, interphase FISH enables researchers to cytoge netically analyse tumors which are only available in preserved form (e . g., in paraffin) or of which evaluable metaphases could not be obtai ned by labor intensive cell culturing. By CGH, the entire genome of tu mor cells can be screened for chromosomal imbalancies as indicated by gains and losses of tumor DNA. In this review, the techniques of molec ular cytogenetics are detailed, and recent findings in hematological m alignancies are summarized, with particular focus on implications for diagnosis and prognostic assessment. Interphase FISH proved valuable n ot only to sensitively detect chromosomal changes pathognomic for acut e myelogenous leukemia, but also to provide novel insights into cytoge netic abnormalities of chronic lymphocytic leukemia and multiple myelo ma. In these diseases, previously underestimated chromosomal abnormali ties (in particular deletions of p53 gene and 11q) were shown to be of major prognostic si,significance. Furthermore, recent studies indicat e that FISH may also be of value for the management of patients with c hronic myelogenous leukemia.