Differential Gene Expression in Apoptosis: Identification of Ribosomal Protein 23K, a Cell Proliferation Inhibitor

Gene expression during the camptothecin-induced apoptotic death of human leukemic U937 cells and mouse T-cell hybridoma QW4.1 cells was studied by the mRNA differential display technique. Ten clones were confirmed to be differentially expressed, nine of which encoded novel sequences. One clone, U3.2, was induced approximately 10-fold in camptothecin-treated cells and was found to be identical to a highly basic 23-kDa human protein which contains basic leucine zipper-like motifs and has recently been identified as the human homologue of the rat ribosomal protein L13a. Northern blot analysis revealed a major mRNA of 0.9 kb and a minor mRNA of 1.3 kb. Overexpression of a full-length 23K cDNA, tagged with a FLAG sequence, in COS-7 cells revealed a predominantly nucleolar localization and the absence of any 23K protein from the cytoplasm. Subsequent transfection studies, using antisense phosphorothioate-modified oligonucleotides, revealed that inhibition of 23K expression results in an increased cell proliferation and greater sensitivity of U937 cells to the effects of camptothecin-induced cell death. Upregulation of 23K expression using a cDNA construct resulted in a decrease in cell proliferation and growth arrest, suggesting a role for 23K protein as a proliferation checkpoint following a cellular insult.     

Interferon-α is a Potent Inhibitor of Basic Fibroblast Growth Factor-Stimulated Cell Proliferation in Human Uterine Cells

PROBLEM: Abnormal uterine bleeding is a significant health problem for many women and is the number-one reason for performing hysterectomy in the United States. Leiomyomas (uterine fibroids) are benign neoplams that are a frequent cause of abnormal uterine bleeding. The goal of this study was to assess the effects of the anti-angiogenic cytokine, interferon (INF)-α, on the proliferation of both leiomyoma and normal uterine cells. METHOD OF STUDY: Primary cultures of leiomyoma, myometrial, and endometrial stromal cells were established for in vitro study. The effects of INF-α (10, 100, and 1000 U/ml) were tested on serum-stimulated and basic fibroblast growth factor-stimulated cell proliferation using the [³H]thymidine incorporation assay. RESULTS: INF-α was a potent inhibitor of cell proliferation for all three cell types, with endometrial stromal cells showing the greatest sensitivity. The antiproliferative effect did not appear to result from toxic effects on the cells. CONCLUSION: INFs may prove to be useful therapeutic agents for the treatment of leiomyoma-related abnormal uterine bleeding.     

Transforming Growth Factor Beta Stimulates Mitogenically Mouse NIH3T3 Fibroblasts and Those Cells Transformed by the EJ-H-ras Oncogene

Abstract

TGF-β1 stimulates thymidine incorporation and the growth rate of mouse NIH3T3 fibroblasts and of those cells transformed by the EJ-H-ras oncogene (TR15 cells), in the presence and the absence of serum. Thymidine incorporation, in serum-deprived cells, is stimulated to a higher degree by 0.1-1 ng/ml of TGF-β in NIH3T3 than in TR15 cells, which have a 10-fold higher basal level of incorporation. In both cell types TGF-β1 is as active, or more active than other mitogens (TGF-α, PDGF-AB, bFGF) at the same concentration. The growth rate of NIH3T3 cells, in low serum or serum-free (S^?) medium, is stimulated by only 10 picograms/ml of TGF-β1, and that of TR15 cells, in S^? medium, by only 1 picogram/m1. In contrast, TGF-β1 inhibits mitogenically unestablished mouse embryo fibroblasts and these fibroblasts immortalized spontaneously and able to grow in S^? medium. It also inhibits the anchorage-independent growth of TR15 cells. NIH3T3 and TR15 cells respond, similarly, to TGF-β activated by acification of their culture medium. The kinetics of thymidine incorporation and of activation of the c-myc proto-oncogene, observed already after 1 hr, in treated NIH3T3 and TR15 cells, suggests a direct mitogenic stimulation. The level of activated c-myc RNA is 2-fold higher at 2 hr, and subsequently decreases relatively less in the TR15 cells.     

碱性成纤维细胞生长因子对骨髓间充质干细胞向颞下颌关节盘细胞分化的影响

为观察碱性成纤维细胞生长因子(bFGF)对骨髓间充质干细胞(BMSCs)分化的影响,采用bFGF诱导山羊BMSCs,通过组织学、免疫组织化学和酶联免疫吸附实验(ELISA)等方法检测BMSCs产生的细胞外基质(ECM)包括Ⅰ型胶原和蛋白多糖的情况,初步评价BMSCs做为颞下颌关节(TMJ)盘组织工程种子细胞的可行性。结果表明:经bFGF诱导,BMSCs向成纤维细胞样细胞分化,能够合成糖胺聚糖(GAG)和I型胶原,因此认为BMSCs作为工程化关节盘种子细胞是可行的。     

鼠表皮生长因子受体胞外段原核表达、纯化与复性

用多聚酶链反应(PCR)方法从既往构建质粒扩增鼠表皮生长因子受体(EGFR)胞外段基因及适宜酶切位点，进而构建原核表达载体。克服质粒丢失的不足，在大肠杆菌中表达目的蛋白，并在变性条件下通过。Ni^2 柱亲和层析纯化表达蛋白，聚丙烯酰胺凝胶电泳(SDS—PAGE)示纯度在95％以上。去除组氨酸标记的纯化蛋白在梯度尿素中透析复性。复性蛋白在表皮生长因子的作用下可以同源二聚化而在非还原SDS—PAGE及蛋白印迹分析中呈二聚体状态，其所产生抗体可以识别复性蛋白及表达于肺癌细胞上的EGFR，提示复性后大肠杆菌表达鼠EGFR胞外段重组蛋白已获得一定空间结构，并具有免疫原性，可以进一步用于EGFR功能及免疫学研究。     

钙调神经磷酸酶抑制剂对过氧化氢诱导的干细胞凋亡的影响简

目的比较钙调神经磷酸酶（CAN）抑制剂FK-506和环孢菌素A（CsA）保护脂肪组织来源干细胞（AT-DSCs）抗凋亡作用及可能机制。方法采用过氧化氢（H2O2）[分浓度0（对照组）、50、100、200、300、400μmo/LH2O26组]体外诱导AT-DSCs凋亡模型．凋亡模型的评价采用磷脂酰丝氨酸结合蛋白-异硫氰酸荧光素（AnnexinV-FITC）／碘化丙啶（PI）双染流式细胞术和线粒体内跨膜电位测定法;观察AT-DSCs凋亡细胞形态;AT-DSCs细胞活性检测采用CCK-8试剂;细胞色素C的表达采用Westernblot分析。结果与对照组比较,引起细胞凋亡率最高的是浓度100μmol／LH20,（15．60％±8．50％±4．50％±0．88％;p〈0．01）;但CaN抑制剂FK-506（质量浓度1mg／mL）（9．8％±1．3％Vs17．0％±1．6％,P〈0．01）和CsA（质量浓度1mg／mL）（12．2％±1．2％Vs17．0％4±1．6％,P〈0．01）预处理后细胞凋亡率均明显下降,细胞存活率明显提高（P〈0．01）。Western blot结果显示．CaN抑制剂FK-506（质量浓度1mg／mL）和CsA（质量浓度1mg／mL）可完全抑制H2O2诱导的细胞色素C释放。结论CaN抑制剂能保护H2O2诱导的干细胞凋亡。可能机制是CaN抑制剂能抑制细胞凋亡,提高细胞存活率,下调细胞色素C的释放。     

Terminal Differentiation of Mouse Preadipocyte Cells: The Mitogenic-Adipogenic Role of Growth Hormone is Mediated by the Protein Kinase C Signalling Pathway

Abstract

The role of growth hormone (GH) in the differentiation process of Obi 771 mouse preadipocyte cells has been studied under culture conditions that were serum-free and hormone-supplemented and which were previously shown to lead to terminal differentiation. In the absence of GH, a dramatic decrease in the adipogenic activity of the culture medium could be observed, as indicated 12 days after confluence by the low levels of glycerol-3-phosphate dehydrogenase activity and the sharp reduction of the number of triacylglycerol-containing cells. This decrease in adipogenic activity was accompanied by a parallel loss of the mitogenic potency of the culture medium. Determination of the half-maximal and maximal concentrations of GH required for the restoration of growth and differentiation were identical, 0.5 and 2 nM, respectively. Despite the presence of insulin-like growth factor-I (IGF-I) to substitute for supraphysiological concentrations of insulin and to saturate IGF-I receptor, GH was still required to induce terminal differentiation of a maximal number of cells. However, protein kinase C activators such as prostaglandin F₂a, phorbol esters and diacylglycerol were able to mimic GH in promoting a maximal mitogenic-adipogenic response, indicating that the ability of GH to induce diacylglycerol production (Doglio et al., 1989; Catalioto et al., 1990) plays a prominent role in this process. Furthermore, in agreement with the fact that the mitoses which precede terminal differentiation of Obi 771 preadipocytes are strictly controlled by cAMP and only modulated by protein kinase C., terminal differentiation of Ob 1771 preadipocytes occured in the absence of GH upon supplementation with high concentrations of carbaprostacyclin, added as a cAMP-elevating agent or with 8-Br-cAMP, added as a cAMP analogue. It is concluded that the control exerted by GH on terminal differentiation of mouse preadipocytes corresponds to a modulating mitogenic effect mediated through protein kinase C activation and leading to a potentiation of the cAMP and IGF-I mitogenic signalling pathways.     

Nerve Growth Factor (NGF) Responses by Non-Neuronal Cells: Detection by Assay of a Novel NGF-Activated Protein Kinase

Past work described the partial purification and characterization of a novel serine protein kinase activity designated protein kinase N (PKN) that is activated by nerve growth factor (NGF) in cultured PC12 cells [Rowland et al. (1987) J. Biol. Chem. 262; 7504–7513]. We have now devised a rapid, sensitive technique for partially purifying and assaying PKN activity in cell extracts. This methodology was applied to the IARC-EW-1 osteosarcoma and several additional non-neuronal cell lines that possess NGF receptors but that lack both morphological and a variety of additional biochemical responses to NGF. In each case, NGF significantly elevated PKN activity. The assay also revealed activation of PKN activity in IARC-EW-1 cells by additional agents, including epidermal growth factor, fibroblast growth factor, phorbol ester, and a cAMP analog. Also tested were an NGF-receptor-deficient PC12 cell variant and sublines thereof into which human NGF receptors had been introduced [Hempstead et al. (1989) Science 243; 373–375]. Acquisition of the NGF receptors resulted in NGF-activatable PKN activity. These findings indicate that detection of PKN activity may serve as a sensitive means to test NGF responsiveness in cells lacking macroscopic responses to the factor and that non-neuronal cells may be useful for studying primary signaling events in the NGF mechanism of action.     

Nerve Growth Factor (NGF) Responses by Non-Neuronal Cells: Detection by Assay of a Novel NGF-Activated Protein Kinase

Abstract

Past work described the partial purification and characterization of a novel serine protein kinase activity designated protein kinase N (PKN) that is activated by nerve growth factor (NGF) in cultured PC12 cells [Rowland et al. (1987)J. Biol. Chem. 262; 7504-75131. We have now devised a rapid, sensitive technique for partially purifying and assaying PKN activity in cell extracts. This methodology was applied to the IARC-EW-1 osteosarcoma and several additional non-neuronal cell lines that possess NGF receptors but that lack both morphological and a variety of additional biochemical responses to NGF. In each case, NGF significantly elevated PKN activity. The assay also revealed activation of PKN activity in IARC-EW-1 cells by additional agents, including epidermal growth factor, fibroblast growth factor, phorbol ester, and a cAMP analog. Also tested were an NGF-receptor-deficient PC12 cell variant and sublines thereof into which human NGF receptors had been introduced [Hempstead et al. (1989) Science 243; 373-375]. Acquisition of the NGF receptors resulted in NGF-activatable PKN activity. These findings indicate that detection of PKN activity may serve as a sensitive means to test NGF responsiveness in cells lacking macroscopic responses to the factor and that non-neuronal cells may be useful for studying primary signaling events in the NGF mechanism of action.     

Fibroblast growth factor 8 induced downregulation of thrombospondin 1 is mediated by the MEK/ERK and PI3K pathways in breast cancer cells

Expression of fibroblast growth factor 8 (FGF-8) is increased in several forms of hormonal cancer. It was previously shown to regulate expression of thrombospondin 1 (TSP-1), an inhibitor of angiogenesis, in S115 breast cancer cells. Here, we studied the FGF-8-activated signalling pathways mediating TSP-1 repression in S115 cells and in non-tumorigenic MCF10A cells. Inhibition of FGF receptors or of MEK1/2 and PI3K with specific inhibitors (PD173074, U0126 or LY294002, respectively) restored TSP-1 mRNA expression in the presence of FGF-8 in S115 cells. Furthermore, U0126 and LY294002 increased TSP-1 mRNA expression in S115 cells over-expressing FGF-8. In MCF10A cells, FGF-8 treatment also decreased TSP-1 expression and the effect was dependent on active MEK1/2. In conclusion, FGF-8 suppresses TSP-1 expression through two independent pathways, MEK1/2 and PI3K. Repression of TSP-1 may be an important mechanism involved in induction of an angiogenic phenotype and growth of FGF-8-expressing breast cancer.     

The Potential Role of Platelet-Derived Growth Factor as an Autocrine or Paracrine Factor for Human Bone Cells

Platelet-derived growth factor, PDGF, is a potent mitogen for cells of mesenchymal origin such as fibroblasts, smooth muscle cells and glial cells. PDGF is thought to have the potential to act as both a paracrine and an autocrine factor. Studies described here extend these observations to human bone-derived cells. Exogenous PDGF induces biologic activity in two human osteogenic sarcoma cell lines and in one of these, the two PDGF genes, PDGF-1 and PDGF-2/c-sis are expressed. In addition, PDGF stimulates proliferation of normal osteoblastic cells derived from adult human cancellous bone. The expression of the PDGF-1 gene but not the PDGF-2/c-sis gene is demonstrated in normal human adult bone-derived cells by Northern blot analysis and synthesis of PDGF is shown by immunoprecipitation with PDGF antisera. These studies indicate that PDGF has the potential to act as a paracrine or autocrine regulator of bone cells.     

Susceptibility to viral infection is enhanced by stable expression of 3A or 3AB proteins from foot-and-mouth disease virus

The foot-and-mouth disease virus (FMDV) 3A protein is involved in virulence and host range. A distinguishing feature of FMDV 3B among picornaviruses is that three non-identical copies are encoded in the viral RNA and required for optimal replication in cell culture. Here, we have studied the involvement of the 3AB region on viral infection using constitutive and transient expression systems. BHK-21 stably transformed clones expressed low levels of FMDV 3A or 3A(B) proteins in the cell cytoplasm. Transformed cells stably expressing these proteins did not exhibit inner cellular rearrangements detectable by electron microscope analysis. Upon FMDV infection, clones expressing either 3A alone or 3A(B) proteins showed a significant increase in the percentage of infected cells, the number of plaque forming units and the virus yield. The 3A-enhancing effect was specific for FMDV as no increase in viral multiplication was observed in transformed clones infected with another picornavirus, encephalomyocarditis virus, or the negative-strand RNA virus vesicular stomatitis virus. A potential role of 3A protein in viral RNA translation was discarded by the lack of effect on FMDV IRES-dependent translation. Increased viral susceptibility was not caused by a released factor; neither the supernatant of transformed clones nor the addition of purified 3A protein to the infection medium was responsible for this effect. Unlike stable expression, high levels of 3A or 3A(B) protein transient expression led to unspecific inhibition of viral infection. Therefore, the effect observed on viral yield, which inversely correlated with the intracellular levels of 3A protein, suggests a transacting role operating on the FMDV multiplication cycle.     

Cloning of a DNA fragment from Cephalosporium acremonium which functions as an autonomous replication sequence in yeast

Summary A fragment of DNA which functions as an autonomous replication sequence in yeast was cloned from Cephalosporium acremonium. Mitochondrial DNA (mtDNA) was isolated from an industrial strain of C. acremonium (08G-250-21) highly developed for the production of the antibiotic, cephalosporin C. Size, 27 kb, and restriction pattern indicated this DNA was identical to mtDNA previously isolated (Minuth et al. 1982) from an ancestral strain (ATTC 14553) which produces very low amounts of cephalosporin C. A 1.9 kb Pst1 fragment of the Cephalosporium mtDNA was inserted into a Pst1 site of the yeast integrative plasmid, Ylp5, to produce a 7.5 kb plasmid, designated pPS1. The structure of pPS1 was verified by restriction analysis and hybridization.PS1 transformed Saccharomyces cerevisiae (DBY-746) to uracil prototrophy at a frequency of 272 transformants/g DNA. Transformation frequencies of 715 transformants/g DNA and zero were obtained for the replicative plasmid, YRp7, and the integrative plasmid YIp5, respectively. Southern hybridization and transformation of E. coli by DNA from yeast transformed by pPS1 verified that pPS1 replicates autonomously in yeast.The uracil-independent pPS1-yeast transformants were mitotically unstable. The average retention of pPS1 after three days growth in selective and non-selective medium was 4.5% and 0.4%, respectively, compared to retentions of 4.6% and 0.5% for YRp7. The properties of pPS1 were compared to those of a related plasmid, pCP2. pCP2 was constructed (Tudzynski et al. 1982) by inserting the C. acremonium 1.9 kb Pst1 fragment into the yeast integrative plasmid, pDAM1.     

Interleukin-1 receptor associated kinase 1 is a potential therapeutic target of anti-inflammatory therapy for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease and currently has no effective therapy. The genome-wide analyses indicate that interleukin-1 receptor associated kinase 1 (IRAK1) is associated with the susceptibility of SLE in humans. In the present study, we identified that IRAK1 was overexpressed and hyper-activated in splenic mononuclear cells from B6.MRL-Fas^lpr/Nju (B6.lpr) mice and peripheral blood mononuclear cells (PBMCs) from SLE patients. Intraperitoneal treatment with a small molecular inhibitor of IRAK1 (IRAK1/4 inhibitor or IRAK-Inh) significantly mitigated inflammatory responses and renal injury in B6.lpr mice. IRAK-Inh treatment or knockdown of IRAK1 by specific siRNA decreased the relative levels of NF-κBp65 phosphorylation in human PBMCs from SLE patients. Therefore, IRAK1 may be a potential target for anti-inflammatory therapy for SLE and other inflammatory diseases.     

Follicular lymphoma of the skin and superficial soft tissues associated with a prominent follicular dendritic cell proliferation: an unusual pattern which may represent a diagnostic pitfall

We describe two elderly patients with follicular lymphoma (FL) involving the skin and superficial soft tissues, with a striking proliferation of follicular dendritic cells (FDC). In addition, one patient had bone marrow involvement by FL. Histopathologically, the most remarkable feature in both cases seen at low magnification was a striking pallor of the constituent cells, which were arranged in fascicles, whorls, and round islands. The majority of the cells had the typical cytologic features of FDCs. They were intimately intermingled with centroblasts and centrocytes. A large amount of the clear cytoplasm and the pale nuclei of FDCs, which predominated in the tumors, caused the striking overall pallor of the lesions. Small reactive lymphocytes were scattered between the fascicles. A vague follicular growth pattern was seen only focally. The mantle zones were markedly reduced or absent so that the follicles were seen lying unseparated. The close intermixture of the FDCs and the germinal center cells was responsible for the FDCs appearing to be decorated with B-associated marker, and the germinal center cells seemed to be stained to some degree with FDC-markers. The tumor bulk demonstrated a diffuse and strong reaction with CD10, CD20, CD21, CD35, and stained weakly with CD79a. Fascin and CD23 showed only a weak and focal staining pattern. Bcl-2 decorated large centroblasts and small reactive T-cells. The tumor bulk was negative for actin, EMA, cytokeratins, vimentin, desmin, and factor XIIIa. The proliferative index was rather low; MIB-1 mainly decorated large centroblasts. No monoclonal rearrangement of IgH genes was detected. Epstein-Barr virus was not identified. Electron microscopy revealed typical features of FDCs intermingled with germinal center cells. Such cases may represent a diagnostic pitfall, as FDC overgrowth can mask FL and give the neoplasm the appearance of FDC sarcoma/tumor. We believe that, in both cases, the FDC proliferation had a reactive character.     

Secretion of high amounts of hepatocyte growth factor is a characteristic feature of cancer‐associated fibroblasts with EGFR‐TKI resistance‐promoting phenotype: A study of 18 cases of cancer‐associated fibroblasts

Humoral factors from cancer‐associated fibroblasts (CAFs) reportedly affect epidermal growth factor receptor tyrosine kinase inhibitor (EGFR‐TKI) resistance in cancer cells with EGFR mutations. The aim of this study was to identify the robust humoral factors secreted from CAFs that induce the primary resistance to EGFR‐TKI. We evaluated the EGFR‐TKI sensitivity of EGFR‐mutant lung adenocarcinoma cell line (PC‐9) treated with condition media (CM) from 18 cases of CAFs and matched non‐cancerous‐tissue‐associated fibroblasts (NCAFs). We measured the expression levels of hepatocyte growth factor (HGF), interleukin‐6, fibroblast growth factor‐2, insulin‐like growth factor‐1, and vascular endothelial growth factor‐A in CAFs and NCAFs. We examined whether HGF neutralizing antibody could annul the EGFR‐TKI resistance induced by CM from CAFs. Compared to CM from NCAFs, CM from CAFs increased the resistance of PC‐9 cells to EGFR‐TKI in five out of 18 cases. Relative expression ratio of HGF messenger RNA was significantly higher in these five CAFs compared to others (P = 0.0013), whereas other cytokines were not. In four of these five cases, the addition of HGF neutralizing antibody significantly decreased the survival ratio of PC‐9 cells. This study suggests that the secretion of higher amounts of HGF is the robust feature of EGFR‐TKI resistance‐promoting CAFs.     

The delivery of an antigen from the endocytic compartment into the cytosol for cross-presentation is restricted to early immature dendritic cells

Dendritic cells (DCs) are the only antigen-presenting cell population having a cross-presentation capacity. For cross-presentation, however, the intracellular antigen-processing pathway and its regulatory mechanism have not been defined. Here we report the differences in cross-presentation ability among murine bone marrow-derived immature DC, early immature day8-DC and late immature day10-DC, and fully mature day10 + lipopolysaccharide DC. Day8-DCs and day10-DCs show an immature phenotypic profile but are different in morphology. Day8-DCs can internalize an abundant volume of exogenous soluble ovalbumin (OVA) and result in cross-presentation. In contrast, day10-DCs are not able to cross-present, although they maintain efficient macropinocytosis. Exogenously internalized OVA antigens are stored in the endocytic compartments. The endocytic compartments are temporarily maintained at mildly acidic pH in day8-DCs and are rapidly acidified in day10-DCs after uptake of antigens. We show that OVA antigens accumulated in the endocytic compartments move into the cytosol in day8-DCs but do not in day10-DCs. NH(4)Cl-treatment, which neutralizes the acidic endocytic compartments and/or delays endosomal maturation, restores day10-DCs for transport the stored OVA antigens from the endocytic compartments into the cytosol. Diphenyleneiodonium chloride-treatment, which acidifies the endocytic compartments, decreases an amount of transported OVA antigen into the cytosol in day8-DCs. These data indicate that only the early immature stage of DC interferes with endosomal maturation, even after uptake of exogenous antigens, and then transports the antigens into the cytosol.     

High expression of CD34-positive sinusoidal endothelial cells is a risk factor for hepatocellular carcinoma in patients with HCV-associated chronic liver diseases

CD34 has been widely used for the assessment of sinusoid-like neoangiogenesis in hepatocellular carcinoma (HCC). Recently, it was demonstrated that CD34-positive cells isolated from human peripheral blood differentiate into endothelial cells and contribute to neoangiogenesis in adults. We investigated the localization and the substantial role of CD34-positive endothelial cells in the liver with hepatitis C virus (HCV)--associated chronic liver diseases. Liver tissue sections obtained by biopsy from 56 patients with HCV-associated chronic liver diseases by were examined immunohistochemically using anti-CD34, anti-von Willebrand factor (vWF), and anti-vascular endothelial growth factor (VEGF) antibodies. CD34 was stained in the sinusoid, showing dotty, linear, semicircular, or circular patterns. However, sinusoidal expression of vWF was not substantially identified in the same specimens, indicating the existence of sinusoidal CD34-positive but vWF-negative endothelial cells. We classified these cells as CD34 LI and found that CD34 LI was correlated with the expression of VEGF. Among 34 patients with advanced-stage disease, the cumulative incidence of HCC was significantly higher in patients with CD34 LI >or= 12 (n = 16) than in those with CD34 LI < 12 (n = 18; P = .009). Moreover, among several clinicopathologic risk factors, CD34 LI could be recognized as an independently significant factor for development of HCC (relative risk, 7.36; P = .019). We conclude that CD34-positive endothelial cells are regulated by several factors, such as VEGF, and might play a substantial role in hepatocarcinogenesis. Furthermore, high expression of CD34-positive sinusoidal endothelial cells is a risk factor for HCC in patients with HCV-associated chronic liver diseases.