Objective: To evaluate the clinical value of mutated p53 in the peripheral blood of breast cancer patients.
Methods: Plasma DNA of 126 breast cancer patients and 92 healthy women was examined. DNA extraction from the tumor and tissue samples was performed by a nonorganic method. Plasma DNA was purified on Qiagen columns. PCR-SSCP analysis was performed to examine the point mutations in the conserved exons 5, 6, 7 and 8 of TP53.
Results: The mean concentration of plasma DNA was 21 ng/ml in healthy women and 211 ng/ml in patients with breast cancer (P < 0.01). p53 mutations in the primary tumor were detected in 46 of 126 (36.5%) breast cancer patients. Of these 46 patients, 30 (65.1%) were also found to have p53 mutations in their plasma DNA. p53 mutation in plasma DNA was closely correlated with clinical stage, tumor size, lymph node (LN) metastasis and estrogen receptor status (P < 0.05). Survival of the patients with both primary tumor and plasma p53 mutations was the worst. Thirteen of the 22 (59.0%) patients with recurrence and/or metastasis had detectable p53 mutations in their plasma DNA.
Conclusion: p53 mutations in plasma DNA may be a useful prognostic factor and an early marker of recurrence or distant metastasis in breast cancer.