Expression of midkine and its relationship with cell proliferation and apoptosis in pancreatic cancer

Objective To investigate the expression and significance of Midkine(MK) protein and its relationship with cell proliferation and apoptosis in human pancreatic cancer. Methods The immunohistochemical staining (SP) method was used to detect the expression of MK protein and proliferating cell nuclear antigen Ki67 in 49 cases of pancreatic cancer tissues. TUNEL method was used to detect apoptotic index. 15 cases of normal pancreatic tissues were selected as controls. Results The expression of Ki67 and MK were not detected in normal pancreatic tissues,the apoptosis index was less in them (0.63±0.21). The positive expression rate of MK in pancreatic cancer was 77.1% (35/49),the expression of MK was significantly associated with tumor histological grade,clinical stages and lymph node metastasis (P 0.05). The mean Ki67 labeling index (LI) and mean apoptotic index (AI) were (31.67±15.41) and (5.93±4.18) in 49 cases of pancreatic cancer respectively. The mean labeling index of Ki67 was (35.27±16.03) in patients with MK gene positive expression,which was significantly higher than that in patients with negative expression of MK (22.67±13.66),P 0.05. The mean apoptotic index was (5.13±2.69) in patients with MK gene positive expression,which was significantly lower than that in patients with negative expression of MK (7.93±6.65),P 0.05. Conclusions MK is one of the useful indicators,which can reflect the biological behavior of pancreatic cancer. MK may induce the proliferation and inhibit the apoptosis of tumor cells; MK may become a new target in the therapy of pancreatic cancer.