Interleukin 8 in human hepatocellular carcinoma correlates with cancer cell invasion of vessels but not with tumor angiogenesis

Background: Angiogenic factor seems necessary for the development of hepatocellular carcinoma (HCC), which is a hypervascular malignancy. This study examined the expression of interleukin (IL)-8, a potent angiogenic factor, in HCC samples. Methods: We measured IL-8 expression by using reverse transcriptase-polymerase chain reaction in clinical HCC tissues from 45 patients who underwent surgical resection. We then assessed correlations between IL-8 expression and microvessel growth or clinicopathologic factors. We also elucidated the in vitro effect of IL-8 on HepG2 development by using fluorometric assays of proliferation, chemotaxis, and invasion. Results: The expression of IL-8 did not significantly correlate with the microvessel count in HCC tissues, but the incidence of microscopic vessel invasion was significantly higher in IL-8-positive than in IL-8-negative tissues. Thus, more IL-8 was expressed in HCCs at pathologic stage III/IV than in those at stage I/II. Assays in vitro showed that IL-8 stimulates HepG2 chemotactic and invasive activities rather than cell proliferation. Conclusions: The expression of IL-8 in human HCC has more relevance to metastatic potential, such as vessel invasion, than to angiogenesis or cell proliferation.