Advances in Brief p53 Mutation in Plasma DNA and Its Prognostic Value in Breast Cancer Patients

Purpose: Tumor-specific DNA has recently been detected in the plasma of lung, head and neck, breast, and colon cancer patients. Detection of tumor-specific genetic materials in cancer patients at sites distant from the tumor, such as in the blood, may provide a unique and valuable tumor marker for diagnosis and prognosis. Experimental Design: The present investigation was aimed at determining the presence of p53 mutations in the peripheral blood of breast cancer patients and its prognostic value in these patients. Results: In this study, we found that the mean concentration of plasma DNA in healthy women was 21 ng/ml, whereas in patients with breast cancer the mean concentration was 211 ng/ml (P < 0.01). p53 mutations were detected in the primary tumors of 46 of 126 (36.5%) breast cancer p53 mutations in their plasma DNA. p53 mutations in plasma DNA were strongly correlated with clinical stage, tumor size, lymph node (LN) metastasis, and estrogen receptor status (P < 0.05). After a median follow-up of 29 months, univariate and multivariate analysis revealed that both primary tumor and plasma DNA p53 mutations were significant prognostic factors for both relapse-free and overall survival. Furthermore, we demonstrated that patients with both primary tumor and plasma p53 mutations have the worst survival. This outcome occurs in both LN-positive and LN-negative groups. Thirteen of the 22 (59%) patients with recurrence and/or metastasis later had detectable p53 mutations in their plasma DNA. Conclusions: Detection of p53 mutations in plasma DNA may be used as a prognostic factor and an early marker to indicate recurrence or distant metastasis.