Analysis of p53 in the 5q− syndrome. (A) The p53 pathway as shown by the Database for Annotation, Visualization and Integrated Discovery (DAVID) gene ontology application (http://david.abcc.ncifcrf.gov/). Genes highlighted in red are significantly differentially expressed in patients with 5q− syndrome. (B) Double immunostaining for p53 (brown) and Glycophorin A and C (red) in 5q− syndrome (×20, inset ×60) and in normal (×20, inset ×40) bone marrow trephines. Immunostaining was performed on paraffin-embedded tissue sections of normal bone marrow trephines and MDS. The monoclonal antibodies for Glycophorin A (JC159), Glycophorin C (ret40f), and p53 (DO-7) were all obtained from Dako. Images were acquired on a Nikon Eclipse E400 microscope equipped with 10×/0.30, 20×/0.50, 40×/0.75 and 60×/0.85 Plan Fluor objective lenses, using a Nikon DS-5Mc digital camera (all from Nikon) and Adobe Photoshop CS3 Version 10.0.1 image processing/manipulation software (Adobe). In 5q− syndrome, clusters of p53-positive erythroblasts (boxed area shown at higher power in top right inset) were positive for Glycophorin (mature red cells were p53-negative). In the normal bone marrow, clusters of Glycophorin-positive erythroblasts were p53-negative (boxed area shown at higher power in top right inset).