Serum immunosuppressive acidic protein reflects systemic deterioration of colorectal cancer patient condition

Aims: Immunosuppressive acidic protein (IAP) is a potent biological marker for immunological surveillance in patients with malignant tumors. This study aimed to investigate the significance of serum IAP as an index of disease status, clinicopathological findings and prognosis in colorectal cancer. Methods: A total of 101 patients with colorectal cancer and 80 normal volunteers were included in this retrospective trial. Preoperative serum IAP was assayed using a commercially available enzyme-linked immunosorbent assay kit. Results: The serum IAP level in the patients, which was not associated with clinicopathological features except for tumor size, was significantly higher than that in controls. The serum IAP level was closely correlated with percent body weight loss, serum albumin and cholinesterase, and percentage of circulating lymphocytes reflecting the host's nutritional and immunological conditions. Interestingly, these parameters were not associated with factors reflecting disease progression except for tumor size. The prognosis of patients with higher IAP levels was significantly worse than that of patients with lower IAP levels. Furthermore, an elevated serum IAP level was an independent prognostic marker in all patients. Conclusion: The preoperative serum IAP level may reflect the general condition of colorectal cancer patients, and thus may predict long-term survival independently of stage progression.