| ObjectiveHepatocellular carcinoma (HCC) is the sixth most common cancer and the third most common cause of death from cancer worldwide. Although hepatectomy as the optimum therapy for HCC has prolonged patients’survival, it is still difficult to prognose and treat HCC effectively. Hedgehog pathway mostly exists in primary cilium of vertebrate. Generally, PTCH (Patched), which locates at cytomembrane of cilium, can inhibit SMO (Smoothened) to enter cilium and the inhibiting effect will be decreased after SHH (Sonic hedgehog) combines with PTCH. Then SMO will migrate from endosome to cytomembrane of primary cilium and make GLI (Glioma-associated oncogene homolog) protein convert from inactive GLIR to actived GLIA. GLIA will make target gene be transcribed. HH pathway has been found to be importent in several tumors including basal cell carcinoma, myelogenous cancer, prostatic cancer, and breast cancer. However, the role of HH pathway in HCC is still unclear. Therefore, we measured the expression of HH pathway members in HCC cell lines and HCC tissue specimens by RT-PCR and immunohistochemistry for investigating the relationship between HH pathway and HCC clinicopathologic features and further exploring its prognostic value.Materials and MethodsPaired tumors with corresponding peritumoral liver tissues from patients with HCC undergoing curative resection in Zhongshan Hospital during January1999and march2008were randomly enrolled in tissue microarrays (TMAs). Among these specimens,145were used to measure SHH expression,65were used to measure GLI-1expression, and305were used to measure GLI-2expression. All of these proteins were measured by immohistochemistry. Tumor specimens were collected from tumor marginal area without necrosis and all of them were pathologically diagnosed as HCC. Patients did not receive any preoperative anticancer treatment. Normal liver tissues without hepatitis B virus (HBV) infection (negative hepatitis B surface antigen) from40patients underwent liver resection for hepatic hemangioma were randomly recruited. Patients’general information including age, gender, HBV background, and liver cirrhosis and tumor clinicopathological feastures including AFP, tumor size, intrahepatic metastasis, and TMN stage were collected. The mRNA expression of SHH, GLI-1, and GLI-2was measured in HCC cell lines (HCCLM3, MHCC97H, MHCC97L, and HepG2) and normal liver cell line L02by RT-PCR. Relations among SHH, GLI-1, and GLI-2expression, clinicopathologic features, overall survival (OS), and time to recurrence (TTR) were evaluated. Prognostic value of peritumoral SHH, GLI-1, and GLI-2was compared.ResultsIn TMAs, SHH expressed mainly in cytoplasm of HCC cells and peritumoral liver cells. Its expression in tumor tissue was significantly higher than that in corresponding peritumoral tissue (mean IOD,0.0068±0.0107vs0.0053±0.0057, P=0.112), but P value was not significant. GLI-1expressed mainly in cytoplasm of HCC cells and most of interstitial cells, normal liver cells, and peritumoral liver cells were stained negatively. GLI-2expressed mainly in cytoplasm of HCC cells and peritumoral liver cells. Its expression in tumor tissue was significantly higher than that in corresponding peritumoral tissue (0.0058±0.0207vs0.0049±0.0103, P=0.121), but P value was not significant.Intratumoral high SHH expression was positively associated with small tumor size (5.34±0.42vs6.33±0.47, P=0.115) and low TNM stage (P0.112), but P value was not significant. In peritumoral liver tissues, high SHH expression was positively associated with HBV background (P=0.009), liver cirrhosis (P=0.043), and small tumor size (5.13±0.37vs6.84±0.53, P=0.008). The result of Kaplan-Meria analysis demonstrated that both in intratumoral and peritumoral tissues, the overall survival of patients with high SHH expression was better than that of patients with low exprssion (29.78±1.33vs23.68±1.67, P=0.01and28.12±1.17vs25.56±2.08, P=0.021, respectively). GLI-1was not associated with any clinicopathological features and peritumoral high GLI-2expression was associated with small tumor size (5.168±0.61vs6.042±0.53, P=0.051). The result of Kaplan-Mieia analysis demonstrated that the overall survival of patients with peritumoral high GLI-2expression was better than that of patients with low exprssion (28.62±1.47vs26.76±2.38, P=0.051).The mRNA expression of SHH and GLI-2in HCCLM3, MHCC97H, MHCC97L, and HepG2cells were significantly higher than L02cells (P<0.001). However, the difference of SHH and GLI-2expression in these HCC cell lines with different metastasic potential were not significant. The mRNA expression of GLI-1in HCCLM3, MHCC97H, MHCC97L, and HepG2cells were also significantly higher than L02cells (P<0.001) and its expression decreased in parallel with the metastatic potential of the HCC cell lines.ConclusionsHH pathway is associated with HCC carcinogenesis and progression. SHH could be a progostic factor for HCC patients after curative resection.The potential application of this workBoth intratumoral and peritumoral SHH expression could be a progostic factor for HCC patients after curative resection and to explore HH pathway targeting thrapy may be a novel approach to treat HCC.The novelty of this workBoth of HCC intratumoral and peritumoral SHH expression, for the first time, were identified as a potential marker for prognosis in HCC patients after curative resection. |
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