Increased expression of MICA in serum of pancreatic cancer patients

Abstract

Introduction: Major histocompatibility complex class I chain-related A (MICA) is a stress-inducible glycoprotein that is expressed as a transmembrane protein or released as a soluble protein. MICA binds to NKG2D, an activation receptor expressed in natural killer cells and various T cells. MICA expression is increased in a variety of epithelial malignancies, including melanomas, breast, gastric, and colon cancers. We investigated whether serum MICA levels are increased in patients with pancreatic cancer. Methods: Serum of 61 pancreatic cancer patients and 33 healthy volunteers were analyzed for MICA expression using an ELISA kit. Serum MICA levels were correlated with patient demographic and clinicopathologic parameters. Mann-Whitney U test was used to test siginificance. Results: Serum MICA levels of pancreatic cancer patients were significantly higher than in controls (1107 pg/mL vs. 215 pg/ml, p 0.05). Serum MICA levels in patients with resected tumors (n = 24) were significantly lower than in unresected patients (n = 37)(390 pg/mL vs. 1572 pg/mL, p < 0.05). Survival in resected patients (n = 23) was significantly better than in unresected patients (n = 34)(17 months vs. 11 months, p < 0.05). Conclusions: Serum MICA levels are significantly increased in pancreatic cancer patients, and correlate with extent of tumor burden. Surgery may decrease serum MICA levels and improve survival.