Relationships between local and systemic expression of interleukin-12 and plasma levels of vascular endothelial growth factor in patients with gastric cancer.

Background: Interleukin 12 (IL-12) is a heterodimeric cytokine that exhibits potent anti-tumor and anti-metastatic activities. Very few studies have investigated the expression of IL-12 in patients with gastric cancer. The purpose of the present study was to evaluate the immunohistochemicalexpressionandserumlevelsofIL-12, and plasma levels of vascular endothelial growth factor (VEGF) in patients with gastric cancer. Patients and Methods: IL-12 was immunohistochemically stained using monoclonalanti-humanIL-12antibody(1-1A4)insurgical specimens of 27 gastric cancer patients. IL-12-positive cells werecountedandpositivecelldensitywascalculated.Blood was obtained before surgery. Serum levels of IL-12 and plasma levels of VEGF were assessed using the quantitative sandwichenzymeimmunoassaytechnique.Therelationships ofIL-12-positivecelldensity,serum levels of IL-12,plasma levels of vascular endothelial growth factor (VEGF) and clinicopathologicalfactorswereevaluated.Results:Although IL-12-positive cell density was not associated with serum levels of IL-12, the IL-12-positive cell density tended to increaseinpatientswithserumlevelsofIL-12higherthanthe mean level (p=0.0518). IL-12-positive cell density significantly decreased in the patients with CEA positive or differentiated type. Moreover, IL-12-positive cell density tendedtobeinverselycorrelatedwithplasmalevelsofVEGF (p=0.0801,r=-0.343).Conclusion:Theseresultssuggestthat theimmuneefficiencyinpatientswithgastriccancermaybe reflectedbyIL-12-positivecelldensityandserumlevelsofIL- 12. Thus, patients with low IL-12-positive cell density or serumlevelsofIL-12ingastriccancermayrequireadditional immunochemotherapyaftersurgery.