Midkine and syndecan‑1 levels correlate with the progression of malignant gastric cardiac adenocarcinoma.

The present study aimed to determine whether the expression levels of midkine (MK) and syndecan‑1 correlate with the malignant progression and poor prognosis of gastric cardiac adenocarcinoma (GCA). GCA tissue samples (n=72) were obtained from the Department of Pathology of the First Affiliated Hospital of Henan University of Science and Technology (Luoyang, China). The paraffin‑embedded samples had been surgically resected and pathologically diagnosed between 2007 and 2009. Normal gastric cardiac biopsy specimens (n=40) were also collected as the control. The expression levels of MK and syndecan‑1 were assessed by immunohistochemistry using the high‑sensitivity streptavidin‑peroxidase method. Statistical analysis was performed on the data obtained using the SPSS 17.0 statistics package. MK expression was detected in 76.4% of GCA samples and 5% of normal gastric cardiac mucosa specimens. A significant positive correlation was observed between the expression levels of MK and the infiltrative depth of the tumor, the presence of lymph node metastasis and the prognosis of the patients (P<0.05). Syndecan‑1 expression was detected in 38.9% of GCA samples and 100% of normal gastric cardiac mucosa samples. The expression levels of syndecan‑1 were negatively correlated with the grade of differentiation, serosal membrane invasion, lymph node metastasis and the patient's prognosis (P<0.05). Notably, the expression levels of MK and syndecan‑1 were inversely correlated (r=‑0.352, P<0.01) in the GCA tissue samples. These results suggest that high expression levels of MK in GCA tissues may indicate a differentiation stage that is characteristic of malignancy, a late clinical stage and a poor prognosis, whereas increased syndecan‑1 levels may indicate a high degree of differentiation, an early clinical stage and a favorable prognosis. MK and syndecan‑1 may serve as important biomarkers for monitoring the development and progression of GCA.