Hepatic progenitor cell (HPC) marker-positive hepatocellular carcinomas (HCCs) have recently been extensively analyzed, and their prognosis has been reported as poor compared to HPC marker-negative HCCs. However, previous studies have analyzed the existence of HPC marker-positive cancer cells only in primary lesions, as well as the recurrence rate and prognosis of such tumors. Here, we are the first to report the behavior of HPC marker-positive cancer cells during vascular invasion and metastasis of an HCC. We concurrently analyzed EpCAM- and/or NCAM-expressing cancer cells in the primary, vascular invasion, and metastatic lesions of an HCC. An HCC which includes EpCAM- and/or NCAM-expressing cancer cells has not been previously reported. EpCAM- and/or NCAM-positive cancer cells invaded the vessels and formed heterogeneous populations of these HPC marker-positive cancer cells with HPC marker-negative cancer cells. The frequency of HPC marker-positive cancer colonies and cells in vessels was higher than that in the primary HCC. In the metastatic lesions, EpCAM-positive cancer cells were more frequently detected than NCAM-positive cancer cells, indicating that EpCAM may be more important than NCAM for cancer cell settlement in the metastatic lesions. Furthermore, bigger metastatic tumors tended to include HPC marker-positive cancer cells, suggesting that HPC marker-positive cancer cells have a growth advantage in the metastatic lesions. These results showed that HPC marker-positive cancer cells would be important for vascular invasion and metastasis and suggested that HPC marker-positive cancer cells are an important target in HCC treatment.
Metformin prevents hepatocellular carcinoma development by suppressing hepatic progenitor cell activation in a rat model of cirrhosis