Western blot assay of Bcl-2, Bcl-xl, and Bax protein expression from representative ALL cell lines (EU-4 → KT, p53-null lines; EU-6, mutant p53⁺ line; UoC-B1, wt-p53⁺ line). Protein (20 μg) from cell lysates was electrophoresed in SDS-PAGE gels, transferred to nitrocellulose, and probed with anti-Bcl-2, anti-Bcl-x, and anti-Bax as described in the Materials and Methods. Anti-Bcl-x antibody recognizes both Bcl-xl and Bcl-xs forms.