Expression and alteration of insulin-like growth factor II-messenger RNA in hepatoma tissues and peripheral blood of patients with hepatocellular carcinoma

Abstract

To investigate the clinical values of serum free insulin-like growth factor II (IGF-II) levels and IGF-II mRNA in hepatocellular carcinoma (HCC) tissues and peripheral blood for diagnosis of HCC and monitoring of extrahepatic metastasis. Total RNAs were extracted from HCC tissues or peripheral blood mononuclear cells from patients with HCC, liver diseases devoid of cancer, non-hepatic tumors, and healthy controls, respectively. IGF-II cDNAs were synthesized through random primers and reverse-transcriptase, amplified by polymerase chain reaction (PCR), and confirmed by DNA sequencing analysis. Serum free IGF-II levels in patients with different liver diseases were analyzed by an enzyme-linked immunosorbent assay. The amplified fragments of IGF-II mRNA by RT-PCR were identical to originally designed ones with a size of 170 bp and confirmed by sequencing analysis. The dilution experiments revealed that the lowest sensitivity of our system was 2 ng/L of total RNA. The positive frequencies of IGF-II mRNA were 100% in HCC tissues, 53.3% in para-cancerous tissues, and 0% in non-cancerous tissues, respectively. The serum free IGF-II levels were significantly higher in HCC than those in chronic hepatitis or liver cirrhosis. The positive frequency of circulating IGF-II mRNA was 34.2% in HCC, no amplified fragment was found in other liver diseases, extrahepatic tumors, and normal controls, respectively. The circulating IGF-II mRNA correlated with the stage of HCC, and its positive rate was 100% in HCC with extrahepatic metastasis and 35.5% in HCC with AFP-negative. No significant correlation was found between tumor sizes and circulating IGF-II mRNA fragment. The abnormal expressions of free IGF-II and IGF-II mRNA are useful tumor markers for HCC diagnosis, differentiation of extrahepatic metastasis and monitoring postoperative recurrence.