Screening for Trisomy 12 in Bone Marrow from Patients with CLL by the Application of Fluorescence In Situ Hybridization to Interphase Nuclei

Authors: Hasan ACAR, Munis DÜNDAR, Hüseyin YÜCE, Janet STEWART, Michael J. CONNOR

Abstract: Trisomy 12 is the most common chromosomal abnormality in chronic lymphocytic leukemia (CLL) of B-cell origin. We have studied 12 CLL patients with fluorescence in situ hybridization (FISH) to detect trisomy 12 and with conventional cytogenetic trypsin G-banding analysis to detect other chromosomal abnormalities. Fresh uncultured heparanized bone marrow from each patient was analyzed using a chromosome-12-specific a-satellite DNA probe for FISH and also by conventional trypsin G-banding analysis. Two patients (2 of 12) with trisomy 12 were detected by FISH. One of these was confirmed by conventional trypsin G-banding analysis, but the other was not. On conventional cytogenetic analysis, one patient had mosaic trisomy 12, six patients had normal karyotypes, three patient samples failed to produce metaphase spreads, and three patients had different types of chromosomal abnormalities. In conclusion, FISH to interphase nuclei is a sensitive and powerful tool for detecting trisomy 12 in a large number of patients without the need for metaphase preparations.

Keywords: Chronic lymphocytic leukemia, trisomy 12, fluorescence in situ hybridization