Three-year monitoring of serum p53 antibody during chemotherapy and surgery for stage IV rectal cancer.

The overexpression of mutant p53 stimulates serum p53 antibody production in patients with colorectal carcinoma even in superficial tumors. Although the short-term perioperative monitoring of serum p53 antibody titers is reported to be useful in predicting tumor recurrence and patient survival in colorectal carcinoma, the clinical utility of the long-term monitoring of serum p53 antibody titers in patients with colorectal cancer remains unknown. Here, we report the 3-year monitoring of serum p53 antibody titers in a 60-year-old man with rectal cancer, clinical stage IV (T2N2M1b, lung and liver metastases), who was treated with chemotherapy and surgery. Screening tests for CEA (29.4 ng/ml), CA19-9 (41.1 U/ml), and serum p53 antibody (2170 U/ml) were positive before treatment. After chemotherapy with mFOLFOX6 + bevacizumab (B-mab), CEA and CA19-9 decreased to the normal range. However, serum p53 antibody titer remained positive (283 U/ml). After low anterior resection, the serum p53 antibody titer still remained positive (63.4 U/ml). Serum p53 antibody titer significantly changed and was associated with treatment response and tumor recurrence. In the last 6 months of the patient's life, serum p53 antibody titer gradually decreased, which possibly reflects the modification of the patient's immune response to p53 antigens.