Upregulation of PP2Ac predicts poor prognosis and contributes to aggressiveness in hepatocellular carcinoma.

Protein phosphatase 2A (PP2A) is a heterotrimeric protein phosphatase consisting of a 36-kD catalytic C subunit (PP2Ac). This study aimed to explore the prognostic and biological significance of PP2Ac in human hepatocellular carcinoma (HCC). High PP2Ac expression was significantly (P < 0.01) associated with serum hepatitis B surface antigen positivity, serum hepatitis B e antigen positivity, liver cirrhosis, moderate to poor differentiation grade, advanced disease stage, intrahepatic metastasis, and early recurrence in HCC. Multivariate analysis revealed PP2Ac as an independent prognostic factor for overall survival. Enforced expression of hepatitis B virus X protein (HBx) and its carboxyl-terminal truncated isoform induced PP2Ac expression in HCC cells. Co-immunoprecipitation assay revealed a direct interaction between PP2Ac and HBx. Small interfering RNA-mediated knockdown of PP2Ac significantly inhibited in vitro cell proliferation, colony formation, migration, and invasion and reduced tumor growth in an xenograft mouse model. In contrast, overexpression of PP2Ac promoted HCC cell proliferation, colony formation, and tumorigenesis. Additionally, silencing of PP2Ac impaired the growth-promoting effects on HepG2 HCC cells elicited by overexpression of carboxyl-terminal truncated HBx. Gene expression profiling analysis showed that PP2Ac downregulation modulated the expression of numerous genes involved in cell cycle and apoptosis regulation. Collectively, PP2Ac upregulation has a poor prognostic impact on the overall survival of HCC patients and contributes to the aggressiveness of HCC. PP2Ac may represent a potential therapeutic target for HCC.

microRNA-622 acts as a tumor suppressor in hepatocellular carcinoma.

microRNAs (miRNAs) are important regulators of tumor development and progression. In this study, we aimed to explore the expression and role of miR-622 in hepatocellular carcinoma (HCC). We found that miR-622 was significantly downregulated in human HCC specimens compared to adjacent noncancerous liver tissues. miR-622 downregulation was significantly associated with aggressive parameters and poor prognosis in HCC. Enforced expression of miR-622 significantly decreased the proliferation and colony formation and induced apoptosis of HCC cells. In vivo studies demonstrated that miR-622 overexpression retarded the growth of HCC xenograft tumors. Bioinformatic analysis and luciferase reporter assays revealed that miR-622 directly targeted the 3'-untranslated region (UTR) of mitogen-activated protein 4 kinase 4 (MAP4K4) mRNA. Ectopic expression of miR-622 led to a significant reduction of MAP4K4 expression in HCC cells and xenograft tumors. Overexpression of MAP4K4 partially restored cell proliferation and colony formation and reversed the induction of apoptosis in miR-622-overexpressing HCC cells. Inhibition of JNK and NF-κB signaling phenocopied the anticancer effects of miR-622 on HCC cells. Taken together, miR-622 acts as a tumor suppressor in HCC and restoration of miR-622 may provide therapeutic benefits in the treatment of HCC.

Undifferentiated liver embryonal sarcoma in adults: a report of four cases and literature review.

AIM: To evaluate the undifferentiated embryonal sarcoma of liver (UESL) in adults in order to improve its diagnosis and treatment. METHODS: Four primary and one recurrent cases of UESL were clinicopathologically evaluated and immunohistochemically investigated with a panel of antibodies using the EnVision+ system. Relevant literature about UESL in adults was reviewed. RESULTS: Three males and one female were enrolled in this study. Their chief complaints were abdominal pain, weight loss, or fever. Laboratory tests, imaging and pathological features of UESL in adults were similar to those in children. Immunohistochemistry showed evidence of widely divergent differentiation into mesenchymal and epithelial phenotypes. The survival time of patients who underwent complete tumor resection followed by adjuvant transcatheter arterial chemoembolization (TACE) was significantly longer than that of those who underwent surgical treatment alone. CONCLUSION: UESL in adults may undergo pluripotential differentiation and its diagnosis should be made based on its morphological and immunohistochemical features. Complete tumor resection after adjuvant TACE may improve the survival time of such patients.

Primary mixed germ cell tumor of the liver with sarcomatous components.

Germ cell tumor (GCT) of the liver is extremely rare. Here, we describe a case of hepatic mixed GCT with significant sarcomatous components and elevated serum alpha-fetoprotein (AFP) in a 34-year-old man. Histopathologically, the tumor was composed of two GCTs components: yolk sac tumor and immature teratoma. The predominant components of immature teratoma consisted of several types of tissue that represented different germinal layers (endoderm, mesoderm and ectoderm) and showed varying degrees of differentiation with significant sarcomatous components. The yolk sac component showed positivity for AFP and cytokeratin (AE1/AE3). The immature teratoma components showed positivity for varying differentiation markers. Interphase cytogenetic analysis revealed that the yolk sac tumor and immature teratoma were positive for i(12p) and 12p over-representation. In particular, the rhabdomyoblastic components also showed typical i(12p) and 12p overrepresentation. This suggested that sarcomatous components may be associated with dedifferentiation or malignant transformation of certain mesenchymal components within teratoma.