Synergy of urokinase‑type plasminogen activator receptor isomer (D1D2) and integrin α5β1 causes malignant transformation of hepatic cells and the occurrence of liver cancer.

The aim of the present study was to investigate the correlations and possible synergy among the urokinase‑type plasminogen activator receptor (uPAR) isomer D1D2 and integrin α5β1 expression levels, malignant transformation in hepatic cells and the occurrence of liver cancer. The expression site and concentration of uPAR (D1D2) were analyzed using polymerase chain reaction and in situ hybridization at the gene level in 60 samples of hepatocellular carcinoma (HCC) tissues, 60 samples of para‑carcinoma tissues and 25 samples of normal liver tissues. The mRNA levels of uPAR (D1D2) and integrin α5β1 were markedly increased para‑carcinoma tissue and liver cancer tissue as compared with those in normal tissue. The grey values of the three groups were significantly different (P<0.05). In situ hybridization revealed that the expression levels of uPAR (D1D2) and integrin α5β1 in the cytoplasm and the positive rate of the two molecules in the HCC tissue were significantly higher than those in the para-carcinoma and normal liver tissues, and the expression levels were positively correlated (rs1=0.257, P<0.05; rs2=0.261, P<0.05). The results suggested that uPAR (D1D2) mRNA overexpression may be due to changes in the conformation of the uPAR isomer. Synergy of uPAR (D1D2) mRNA and integrin α5β1 interaction may result in abnormal signal transduction in liver cells and ultimately liver cell abnormal clonal hyperplasia and malignant transformation.