Detection of p53 dysfunction.

Irradiated and nonirradiated CLL cells were lysed after 10-hour culture. Protein extracts were subjected to SDS-PAGE and Western blot analysis, as described in “Patients, materials, and methods.” After initially probing for p21, membranes were sequentially stripped and reprobed for p53. To take into account any differences in protein loading, membranes were stripped again and reprobed for BCL-2. Dagger and asterisk denote patients with CLL showing types A and B p53 dysfunction, respectively.