Deletion map of chromosome 9p21. Cases no. 1, 3, 5, 7, and 11 demonstrate homozygous deletion of the region containing the p16 and p15 genes in the progressed DLCL, but not in the corresponding prior LGFCL or normal patient tissue (see text for complete explanation), whereas cases no. 2, 4, and 9 show hemizygous deletion involving these regions. Cases no. 6, 8, and 10 show no evidence of LOH.