(A) Photomicrograph of a dual-color hybridization obtained with YAC clone 755b11 mapping to 11q22.3-11q23.1 (detected via FITC, green) and YAC clone 866e7 mapping to 3q26 (detected via rhodamine, red) to cells of patient no. 6. In three cells, three or four green hybridization signals are seen indicating an overrepresentation of sequences on band 11q22.3-11q23.1 in these cells. In contrast, only two red hybridization signals are present indicating a normal copy number of sequences on band 3q26. (B) Photomicrograph of a dual-color FISH experiment with cosmid probe cos-myc 72, containing sequences of the MYC proto-oncogene detected via rhodamine (red) and the YAC clone 963d6 mapping to band 6q21 detected via FITC (green). In this case (no. 16), CGH analysis showed a strong bandlike hybridization signal at chromosomal band 8q23-24.3. In three of the cells a tight cluster of red hybridization signals is visible indicating an amplification of these sequences. In contrast, two green signals are seen in all cells. (C) Southern blot analysis of DNA of case no. 14 (right) and DNA from a placenta (left) serving as an internal control. Probes for the REL proto-oncogene andMYH7 (control) are marked on the right side. Note the high intensity of the REL signal in this case. Densitometric evaluation showed a sevenfold amplification of this gene.