Detection of genetic markers by FISH in different cell populations of patients with B-CLL.

(A) CD34⁻/AC133⁻ cells displaying (a) heterozygous deletions of both Rb1 and D13S319, (b) heterozygous deletion of Rb1 and homozygous of D13S319, and (c) heterozygous deletion of only Rb1. Red dots (signals) correspond to the Rb1 gene and green ones to the D13S319 locus. Yellow signals are produced by the fusion of red and green signals from Rb1 and D13S319 lying close on the same chromosome (13q14). (B) CD34⁺/AC133⁻cells (green surface staining) with different genetic profile: (a) with presence of 2 red and 2 green signals (no deletions), (b) with heterozygous deletion of D13S319, and (c) with heterozygous deletion of both Rb1 and D13S319. (C) CD34⁺/AC133⁺ cells (red surface staining) with no marker deletions (all 4 signals present).