Cancer Treatment Today

Whereas BRCA testing is well estblished, p53 testing as a single factor is not. P53 is a tumor suppressor gene. Normally, the p53 protein, coded for by the p53 gene stops cells with DNA damage from multiplying until the DNA is repaired naturally or sends the defective cell into programmed cell death. When the p53 gene becomes damaged or mutated, the protein becomes nonfunctional and loses its checkpoint control, allowing cancerous cells to replicate more readily.
A recent study published in the conducted by Dr. Ayman Linjawi of the Royal Victoria Hospital in Montreal, Quebec, Canada reveals that women with early-stage breast cancer who test positive for the mutated p53 tumor suppressor tend to have a poorer breast cancer prognosis than women who do not carry the mutated p53. Dr. Linjawi and colleagues found that the Stage I breast cancer patients with the mutant p53 had an average survival rate of 74% after five years compared with a survival rate of 83% who did not have the mutant p53. p53 mutation testing is available to high-risk women at specialized centers. However, according to the American Cancer Society, this testing has not been shown to be helpful in determining current patients’ treatment at this point. Further research on p53 genetic testing is needed to determine whether it may one day have value in helping physicians choose a breast cancer patient’s best course of treatment.

Westhof G, Olbrecht M, Wolff M, Schiermeier S, Zimmermann RC, Hatzmann W:
Testing of Functional Integrity of p53 Protein in Primary Breast Cancer by a Rapid Quantitative p53-p21WAF1 Double Assay May Improve the Clinical Value of p53.
Tumor Biol 2006;27:252-260

B. L. Sprague, A. Trentham-Dietz, M. Garcia-Closas, P. A. Newcomb, L. Titus-Ernstoff, J. M. Hampton, S. J. Chanock, J. L. Haines, and K. M. Egan
Genetic variation in TP53 and risk of breast cancer in a population-based case control study
Carcinogenesis, August 1, 2007; 28(8): 1680 – 1686.