Figure 1. Figure 2: (a) Carcinoma of the breast with immunohistochemical evidence of p53 overexpression. Intense nuclear staining is evident. P53 associates with nucleolar structures.

Frozen section was stained with anti-p53 antibodies DO-7 by the immunoperoxidase technique, with hematoxylin counterstain. Magnification, x 250.

(b) Western blotting analyses of p53 expressed in nuclear extracts of breast carcinoma cells. As indicated, the anti-p53 antibody detected one band with the classical molecular mass of 53 kDa and another at 45 and 29 kDa. Truncated protein representing the p53 can be seen by smaller size.

Proteins in nuclear extracts were resolved on a 12 % SDS-PAGE and then transferred to a nitrocellulose membrane. p53 present in the nuclear extract were detected with CM-1 antibody (see Materials and methods). This experiment was repeated in triplicate with reproducible results. Lane 1, 2- breast cancer cases

(c) Western blot analysis shows that p53 in nuclear extracts of breast cancer cells also migrated as three closely spaced bands at 38-45 kDa (Lane 1). The arrow indicates a single immunoreactive band representing p53 (Lane 3). Molecular mass markers are presented on the right.

Procedures for SDS-PAGE and Western blot analyses were the same as those used for the experiment described in Figure 2b, and detailed in Materials and Methods. Each analysis was repeated three times with similar results. Lane 1, 2 and 3- breast cancer cases; Lane 4, 5- normal breast tissue