Representative examples of Southern blot analysis of CLL patients. A panel of probes were used for the investigation of clonality (IgH joining region probe), control or loading of total DNA (APC probe), deletion of 13q14.3 region (D13S25 and D13S319 marker probes), and deletion of 13q12 (BRCA2 probe for exon 11, BRCA2-1 and exon 26-27, BRCA2-2, respectively). Except for the patients in lanes 9, 15, and 16 (with <90% clonal B cells population as determined by the JH pattern), all of the other patients are representative examples of patterns included in this study.