Presence of Serum p53 Antibodies is Associated with Decreased In Vitro Chemosensitivity in Patients with Esophageal Cancer

Resistance to chemotherapy remains a serious problem inhibiting the successful treatment of advanced esophageal cancer. A number of studies have revealed that p53 genetic alteration and protein overexpression can predict chemosensitivity. Furthermore, p53 protein overexpression in cancer tissues has been found to induce serum p53 antibodies (p53-Abs). This study was conducted to examine whether analysis of serum p53 Abs could predict the chemosensitivity of esophageal cancer. Serum analysis of p53 antibodies was performed by enzyme-linked immunosorbent assay in 19 patients with esophageal squamous cell carcinoma preoperatively, then surgically resected specimens were stained immunohistochemically for p53 protein expression. Tumor tissues were also analyzed for chemosensitivity by the histoculture drug response assay (HDRA) using cis-dichlorodiammineplatinum(II) (CDDP), 5-fluorouracil (5-FU), and adriamycin (ADM). Serum p53-Abs were present in 47% (9/19) of the patients and immunohistochemical analysis revealed overexpression of p53 protein in 42% (8/19) of the tumors. The presence of serum p53 antibodies was significantly correlated with p53 immunoreactivity (P = 0.005). The inhibition index of patients positive for p53-Abs was significantly lower than that of patients negative for p53-Abs (P < 0.001). This tendency was also observed in the inhibition index to 5-FU. The presence of serum p53-Abs was associated with decreased in vitro chemosensitivity to CDDP and 5-FU. Thus, the detection of serum p53-Abs is suggested to be useful for predicting chemosensitivity in patients with esophageal cancer.