Trisomy 12 in chronic lymphoid leukemias--a metaphase and interphase cytogenetic analysis

Leukemia. 1993 Apr;7(4):516-20.


Trisomy 12 has been shown to be one of the most common chromosome abnormalities in chronic lymphoid leukemias of B-cell origin, and some studies suggested that it predicts poor overall survival. We have prospectively studied 42 patients with B-cell chronic lymphocytic leukemia (B-CLL) and three patients with B-prolymphocytic leukemia (B-PLL) for the incidence of trisomy 12 and other chromosome 12 aberrations applying fluorescence in situ hybridization (ISH) and conventional G-banding analysis. Dual-color hybridization experiments using centromere-12-specific DNA probes were performed for interphase cytogenetics. A subset of patients (n = 11) was analyzed using a DNA library for painting of chromosome 12. The incidence of trisomy/partial trisomy 12 was 18% (8/45 patients; 6/42 with B-CLL and 2/3 with B-PLL) by fluorescence ISH, and 11% (5/45 patients; 4/42 with B-CLL including one patient with partial trisomy 12q13-qter, and 1/3 with B-PLL) on G-banding analysis. Four patients with trisomy 12 were detected by ISH alone. One of these patients only had 4.5% interphase cells with three fluorescence signals indicating the presence of a small subclone with trisomy 12. On G-banding analysis, three of the four patients had a normal karyotype, and one patient had no analyzable metaphases. In conclusion, fluorescence ISH to interphase nuclei is a sensitive method for detecting trisomy 12 in patients with chronic lymphoid leukemias.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosome Banding
  • Chromosomes, Human, Pair 12*
  • DNA Probes
  • Humans
  • In Situ Hybridization, Fluorescence
  • Leukemia, Lymphocytic, Chronic, B-Cell / genetics*
  • Leukemia, Prolymphocytic / genetics*
  • Prospective Studies
  • Trisomy*


  • DNA Probes