Alpha-fetoprotein triggers hepatoma cells escaping from immune surveillance through altering the expression of Fas/FasL and tumor necrosis factor related apoptosis-inducing ligand and its receptor of lymphocytes and liver cancer cells

An Insight Into the Role of Alpha-Fetoprotein (AFP) in the Development and Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the primary malignancy of hepatocytes and the second most common cause of cancer-related mortality across the globe. Despite significant advancements in screening, diagnosis, and treatment modalities for HCC, the mortality-to-incidence ratio remain unacceptably high. A recent study indicates that a minor population of HCCs are AFP negative or express the normal range of AFP levels. Although it is a gold standard and a more reliable biomarker in the advanced stage of HCC and poorly differentiated tumors, it does not serve as a suitable means for screening HCC. AFP plays a significant role in the development and progression of HCC and understanding its role is crucial. By examining the molecular mechanisms involved in AFP-mediated tumorigenesis, we can better understand HCC pathogenesis and identify potential therapeutic targets. This article details the role of alpha-fetoprotein (AFP) in the carcinogenic transformation of hepatocytes. The article also focuses on information about the structure, biosynthesis, and regulation of AFP at the gene level. Additionally, it discusses the immune evasion, metastasis, and control of gene expression that AFP mediates during HCC.

Research Progress in Alpha-Fetoprotein-Induced Immunosuppression of Liver Cancer

Abstract:

Liver cancer is one of the most common malignant tumors, with limited treatment and 8.2% high mortality. Liver cancer is the fourth leading cause of cancer-related deaths, which seriously endangers human life and health. Approximately 70% of liver cancer patients show increased serum alpha-fetoprotein (AFP) levels. AFP is the main diagnostic and prognostic indicator of liver cancer. AFP, a key marker of liver cancer, plays a crucial role in regulating the proliferation of tumor cells, apoptosis, and induction of cellular immune escape. High levels of AFP during embryonic development protect the embryos from maternal immune attack. AFP also promotes immune escape of liver cancer cells by inhibiting tumor-infiltrating lymphocytes (TILs), natural killer cells (NK), dendritic cells (DC), and macrophages; thus, it is also used as a target antigen in immunotherapy for liver cancer. AFP is highly expressed in liver cancer cells. In addition to being used in the diagnosis of liver cancer, it has become a target of immunotherapy for liver cancer as a tumor-associated antigen. In immunotherapy, it was also confirmed that early AFP response was positively correlated with the efficacy of immunotherapy. Early AFP responders had longer PFS and OS than non-responders. At present, the methods of immunotherapy for liver cancer mainly include Adoptive Cell Transfer Therapy (ACT), tumor vaccine therapy, immune checkpoint inhibitors (ICIs) therapy and so on. A large number of studies have shown that AFP mainly plays a role in ACT and liver cancer vaccines. This review presents the research progress of AFP and immunosuppression of liver cancer.

Early Alpha-Fetoprotein Response Is Associated With Survival in Patients With HBV-Related Hepatocellular Carcinoma Receiving Lenvatinib

BACKGROUND/PURPOSE

Lenvatinib is a first-line treatment for unresectable hepatocellular carcinoma (uHCC). We assessed the value of early alpha-fetoprotein (AFP) response for predicting clinical outcomes with lenvatinib treatment in patients with HBV-related uHCC and elevated AFP levels.

METHODS

This retrospective analysis included patients with HBV-related uHCC and baseline AFP levels ≥20 ng/ml who received lenvatinib for >1 month between November 2018 and May 2021. Early AFP response was defined as a >20% decrease in AFP serum level from baseline after 4 weeks of lenvatinib treatment. Radiological response (Response Evaluation Criteria in Solid Tumors v1.1), progression-free survival, and overall survival were assessed in AFP responders and non-responders.

RESULTS

Of the 46 patients analyzed, 30 (65.2%) were early AFP responders and 16 (34.8%) were non-responders. Compared to the non-responders, early AFP responders had a significantly higher objective response rate (34.5% vs 6.3%, p=0.0349), disease control rate (82.8% vs 50.0%; p=0.0203) and longer median progression-free survival (13.0 vs 7.0 months; HR, 0.464; 95% CI, 0.222-0.967; p=0.028). A subsequent multivariate analysis confirmed that early AFP response (HR, 0.387; 95% CI, 0.183-0.992; p=0.0154), Eastern Cooperative Oncology Group Performance Status of 0 (HR, 0.890; 95% CI, 0.811-0.976; p=0.0132) and Albumin-Bilirubin grade 1 (HR, 0.457; 95% CI, 0.269-0.963; p=0.0327) were independent prognostic factors for longer progression-free survival.

CONCLUSION

AFP is an important prognostic factor and a predictive biomarker for survival benefit with lenvatinib treatment in patients with HBV-related uHCC.

Levels of Alpha-Fetoprotein and Association with Mortality in Hepatocellular Carcinoma of HIV-1-Infected Patients

Methods

This is a retrospective cohort study on patients living with HIV-1 infection (PLWH) followed at the Division of Infectious Diseases of the San Raffaele Hospital, with cirrhosis and HCC diagnosed between 1999 and 2018 and with an available AFP value at HCC diagnosis. The area under the receiver operating characteristic curve (AUC) was used to estimate the accuracy of baseline AFP in predicting death. Factors associated with the risk of death were identified using multivariable Cox proportional-hazards regression models.

Results

Overall, 53 PLWH were evaluated: 18 patients received a curative treatment (9 liver transplantation, 5 liver resections and 4 radiofrequency ablation) and 35 a noncurative treatment (17 chemo or radio embolization, 10 sorafenib and 8 best supportive care). Baseline AFP was predictive of death [AUC 0.71, 95% confidence interval (CI) 0.54–0.83], and the optimal cut-off was 28.8 ng/mL. At multivariable analysis, BL AFP ≥28.8 ng/mL was associated with death [adjusted hazard ratio (aHR) 7.05, 95% CI 1.94–25.71 P = 0.003]. Other factors were HBV infection (aHR 8.57, 95% CI 1.47–50.08, P = 0.017) and treatment allocation (curative vs. noncurative, aHR 0.08, 95% CI 0.02–0.40, P = 0.0004).

Conclusions

Our findings suggest that in PLWH AFP serum levels ≥28.8 ng/mL, HBV coinfection and treatment allocation represent predictive markers for death at the time of HCC diagnosis.

Investigation of Potential Molecular Biomarkers for Diagnosis and Prognosis of AFP-Negative HCC

Background

Alpha-fetoprotein (AFP) is the most important diagnostic and prognostic index of hepatocellular carcinoma (HCC). AFP-positive HCC can be easily diagnosed based on the serum AFP level and typical imaging features, but a number of HCC patients are negative (AFP < 20 ng/mL) for AFP. Therefore, it is necessary to develop novel diagnostic and prognostic biomarkers for AFP-negative HCC.

Methods

RNA data from TCGA and differential expression of lncRNAs, miRNAs, and mRNAs were downloaded to analyze the differential RNA expression patterns between AFP-negative HCC tissues and normal tissues. A lncRNA-miRNA-mRNA ceRNA regulatory network was constructed to elucidate the interaction mechanism of RNAs. Functional enrichment analysis of these DEmRNAs was performed to indirectly reveal the mechanism of action of lncRNAs. A PPI network was built using STRING, and the hub genes were identified with Cytoscape. The diagnostic value of hub genes was assessed with receiver operating characteristic (ROC) analysis. And the prognostic value of RNAs in the ceRNA was estimated with Kaplan-Meier curve analysis.

Results

A total of 131 lncRNAs, 185 miRNA, and 1309 mRNAs were found to be differentially expressed in AFP-negative HCC. A ceRNA network consisting of 12 lncRNA, 23 miRNA, and 74 mRNA was constructed. The top ten hub genes including EZH2, CCNB1, E2F1, PBK, CHAF1A, ESR1, RRM2, CCNE1, MCM4, and ATAD2 showed good diagnostic power under the ROC curve; and 2 lncRNAs (LINC00261, LINC00482), 3 miRNAs (hsa-miR-93, hsa-miR-221, hsa-miR-222), and 2 mRNAs (EGR2, LPCAT1) were found to be associated with the overall survival of AFP-negative patients.

Conclusion

This study could provide a novel insight into the molecular pathogenesis of AFP-negative HCC and reveal some candidate diagnostic and prognostic biomarkers for AFP-negative HCC.

Role of Alpha-Fetoprotein in Hepatocellular Carcinoma Drug Resistance

Hepatocellular carcinoma (HCC) is a major type of primary liver cancer and a major cause of cancer-related deaths worldwide because of its high recurrence rate and poor prognosis. Surgical resection is currently the major treatment measure for patients in the early and middle stages of the disease. Because due to late diagnosis, most patients already miss the opportunity for surgery upon disease confirmation, conservative chemotherapy (drug treatment) remains an important method of comprehensive treatment for patients with middle- and late-stage liver cancer. However, multidrug resistance (MDR) in patients with HCC severely reduces the treatment effect and is an important obstacle to chemotherapeutic success. Alpha-fetoprotein (AFP) is an important biomarker for the diagnosis of HCC. The serum expression levels of AFP in many patients with HCC are increased, and a persistently increased AFP level is a risk factor for HCC progression. Many studies have indicated that AFP functions as an immune suppressor, and AFP can promote malignant transformation during HCC development and might be involved in the process of MDR in patients with liver cancer. This review describes drug resistance mechanisms during HCC drug treatment and reviews the relationship between the mechanism of AFP in HCC development and progression and HCC drug resistance.

Alpha-fetoprotein accelerates the progression of hepatocellular carcinoma by promoting Bcl-2 gene expression through an RA-RAR signalling pathway

Previous studies have found that alpha-fetoprotein (AFP) can promote the proliferation of hepatoma cells and accelerate the progression of hepatocellular carcinoma (HCC). However, the exact mechanism of action remains unclear. Recent bioinformatics studies have predicted the possible interaction between AFP and retinoic acid receptors (RARs). Thus, the purpose of this study was to investigate the molecular mechanism through which AFP promotes tumour cell proliferation by interfering with the RA-RAR signal pathway. Our data indicated that AFP could significantly promote the proliferation and weaken ATRA-induced apoptosis of hepatoma cells. Besides, cytoplasmic AFP interacts with RAR, disrupting its entrance into the nucleus, which in turn affects the expression of the Bcl-2 gene. In addition, knockdown of AFP in HepG2 cells was synchronously associated with an incremental increase of RAR binding to DNA, as well as down-regulation of Bcl-2; the opposite effect was observed in AFP gene-transfected HLE cells. Moreover, a similar effect of AFP was detected in tumour tissues with high serum AFP, but not in adjacent non-cancerous liver tissues, or HCC tissues with low serum AFP levels. These results indicate that AFP acts as signalling molecule and prevents RAR from entering into the nucleus by interacting with RAR, thereby promoting the expression of Bcl-2. Our data reveal a novel mechanism through which AFP regulates Bcl-2 expression and further suggest that AFP may be used as a novel target for treating HCC.

AFP promotes HCC progression by suppressing the HuR-mediated Fas/FADD apoptotic pathway

Hepatocellular carcinoma (HCC) is a major leading cause of cancer-related death worldwide. Alpha fetoprotein (AFP) is reactivated in a majority of hepatocellular carcinoma (HCC) and associated with poor patient outcomes. Although increasing evidence has shown that AFP can regulate HCC cell growth, the precise functions of AFP in hepatocarcinogenesis and the associated underlying mechanism remain incompletely understood. In this study, we demostrated that depleting AFP significantly suppressed diethylnitrosamine (DEN)-induced liver tumor progression in an AFP gene-deficient mouse model. Similarly, knocking down AFP expression inhibited human HCC cell proliferation and tumor growth by inducing apoptosis. AFP expression level was inversely associated with the apoptotic rate in mouse and human HCC specimens. Investigation of potential cross-talk between AFP and apoptotic signaling revealed that AFP exerted its growth-promoting effect by suppressing the Fas/FADD-mediated extrinsic apoptotic pathway. Mechanistically, AFP bound to the RNA-binding protein HuR, increasing the accumulation of HuR in the cytoplasm and subsequent inhibition of Fas mRNA translation. In addition, we found that inhibiting AFP enhanced the cytotoxicity of therapeutics to AFP-positive HCC cells by activating HuR-mediated Fas/FADD apoptotic signaling. Conclusion: Our study defined the pro-oncogenic role of AFP in HCC progression and uncovered a novel antiapoptotic mechanism connecting AFP to HuR-mediated Fas translation. Our findings suggest that AFP is involved in the pathogenesis and chemosensitivity of HCC and that blockade of AFP may be a promising strategy to treat advanced HCC.

Restraint stress of male mice induces apoptosis in spermatozoa and spermatogenic cells: role of the FasL/Fas system†

The mechanisms by which psychological stress impairs semen quality are largely unknown. By using a restraint-stressed mouse model, we studied the role of the FasL/Fas system in psychological stress-induced apoptosis of spermatozoa and spermatogenic cells. Male mice were restrained for 48 h before examination for sperm fertilizing potential and for apoptosis and FasL/Fas expression in spermatozoa, spermatogenetic cells/seminiferous tubules, and caudae epididymides. The results showed that the male restraint reduced motility, fertilization rates, and mitochondrial membrane potential while increasing apoptosis and Fas expression in spermatozoa. Restraint also facilitated apoptosis and FasL/Fas expression in spermatogenic cells/seminiferous tubules and caudae epididymides. The restraint-induced apoptosis in spermatozoa and spermatogenic cells was significantly ameliorated in gld mice that harbor a loss-of-function mutation in FasL. However, incubation with FasL did not affect sperm motility and apoptosis, while incubation with tumor necrosis factor (TNF)-α did. The epididymis of the gld mice produced significantly less TNF-α and TNF-related apoptosis-inducing ligand (TRAIL) than that of wild-type mice did after male restraint. Thus, the results confirmed that the FasL/Fas system played an important role in the psychological stress-induced apoptosis of spermatozoa and spermatogenic cells and that FasL triggered sperm apoptosis in epididymis dependently through promoting TNF-α and TRAIL secretion.

Post-treatment alpha-fetoprotein response predicts prognosis of patients with hepatocellular carcinoma: A meta-analysis

BACKGROUND

Post-treatment alpha-fetoprotein (AFP) response has been reported to be associated with prognosis of hepatocellular carcinoma (HCC) patients, but the results were not consistent. This meta-analysis aimed to explore the relationship between AFP response and clinical outcomes of HCC.

METHODS

PubMed, Embase, Medline and Cochrane library were searched for relevant articles published before March 20, 2019. The data were analyzed using RevMan5.3 software.

RESULTS

Twenty-nine articles with 4726 HCC patients were finally included for analysis. The pooled results showed that post-treatment AFP response was significantly associated with overall survival (OS) (hazard ratio (HR) = 0.41, 95% confidence interval (CI): 0.35-0.47, P <.001), progression free survival (PFS) (HR = 0.46, 95% CI: 0.39-0.54, P <.001) and recurrence free survival (RFS) (HR = 0.41, 95% CI: 0.29-0.56, P <.001) of HCC patients.

CONCLUSION

post-treatment AFP response might be a useful prognostic marker for HCC patients.

The role of ERCC1 and AFP gene polymorphism in hepatocellular carcinoma

The aim of this study was to evaluate the effects of polymorphisms in excision repair cross-complementation group 1 (ERCC1) and alpha-fetoprotein (AFP) genes and their haplotypes on the susceptibility to hepatocellular carcinoma (HCC), and to decipher the association between single-nucleotide polymorphisms (SNPs) and clinicopathologic characteristics of HCC.Peripheral blood DNA was extracted from 206 subjects. SNaPshot technique was used for genotyping 5 SNP sites of the ERCC1 rs735482, rs1046282, rs3212948, and AFP rs737241, rs4024 genotypes. Chi-squared test and logistic regression model were used to analyze the relationship of different genotypes or haplotype and the susceptibility and clinicopathologic characteristics of HCC.The frequency of GG.GA and AA genotypes at the AFP rs737241 site in the case and control groups showed statistically significant differences (P < .05). The risk of HCC in subjects carrying mutated allele A (GA+AA) was increased by 0.543-times (P < .05) compared to that in the subjects with the GG genotype. Significant differences were observed in the linkage disequilibrium between 2 of the five SNPs (P < .05); the frequency of ERCC1 C-C and AFP A-A haplotypes was significantly lower in the case group than in the control group (P < .05). The results of clinicopathologic analysis showed that A allele at the rs737241 locus could increase the expression level of AFP (P = .007), the rs1046282 mutation C allele could increase the AFP expression level (P = .011), rs4024 locus mutation A allele could reduce the risk of vascular invasion (P = .013), rs3212948 locus mutation T allele could reduce the differentiation of liver cancer (P = .022), rs1046282 locus C allele could reduce the DNA load of hepatitis B virus (P = .035), and rs735482 A allele could increase the tumor size in HCC (P = .037).The SNPs in rs737241 for AFP gene may correlate with the occurrence of HCC. The SNPs in ERCC1 and AFP genes may affect the prognosis of HCC, offering reliable information for early prediction of tumor progression and diagnosis of HCC.

Drug-eluting bead transarterial chemoembolization is efficient and well-tolerated in treating elderly Chinese hepatocellular carcinoma patients

This study aimed to evaluate the efficacy and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE), and to explore its prognostic factors in elderly Chinese hepatocellular carcinoma (HCC) patients. 93 elderly HCC patients undergoing DEB-TACE were prospectively enrolled. Treatment response was assessed by mRECIST criteriaat1 month post DEB-TACE treatment, and progression free survival (PFS) and overall survival (OS) were calculated. Liver function and adverse events (AEs) within 1 month post DEB-TACE were documented. Complete response (CR) rate and objective response rate (ORR) were 18.3% and 87.1%, respectively. Additionally, medians of PFS and OS were 9.0 months and 21.0 months, respectively. Multivariate logistic regression revealed that no factor independently predicted CR achievement, while tumor size ≥5.0 cm and AFP abnormal were independent factors for predicting both shorter PFS and OS, and higher BCLC stage was an independent predictive factor for unfavorable OS. As to safety profiles, the percentages of patients with abnormal TBIL, ALT, AST, and ALP were increased at 1 week, while they were not different at 1 month post DEB-TACE treatment compared with baseline. Most frequent AEs were pain, fever, nausea or vomiting; skin discolorations, myelosuppression, and other AEs were relatively rare. In conclusion, DEB-TACE was efficient and well tolerated in elderly HCC patients, and increased tumor size, abnormal AFP, as well as higher BCLC stage could be independent markers for predicting worse prognosis.

Hepatic resection after transarterial chemoembolization increases overall survival in large/multifocal hepatocellular carcinoma: a retrospective cohort study

To investigate the prognosis of transarterial chemoembolization (TACE) followed by hepatic resection (HR) in large/multifocal hepatocellular carcinoma (HCC), the medical records of consecutive HCC patients who underwent TACE between January 2006 and December 2010 were retrospectively analyzed. Patients who received TACE alone comprised the T group (61 patients), while those who received HR after TACE comprised the T+R group (49 patients). All the resections were successfully performed, and only one class V complication occurred. While liver function was altered from baseline within 1 week after HR, it recovered within 1 month. Overall survival (OS) of the T+R and T groups were compared, and sub-group analyses were performed based on baseline α-fetoprotein (AFP) levels, the reduction of AFP, and tumor response before HR. Overall survival (OS) in the T+R group was longer than in the T group (47.00 ± 2.87 vs. 20.00 ± 1.85 months, P < 0.001). OS in the T+R group with AFP reduction was less than 50%, and OS among those with a poor tumor response before HR did not differ from the T group (P > 0.05). These patients may not benefit from the combined treatment. Our findings suggest HR after TACE is safe and effective for large/multifocal HCC, and prolongs OS when compared to TACE alone.

Icaritin inhibits the expression of alpha-fetoprotein in hepatitis B virus-infected hepatoma cell lines through post-transcriptional regulation

Although it has showed that icaritin can apparently suppress growth of HCC by reducing the level of AFP, the intrinsic mechanism remains unclear. In this study, we explored the possible mechanism of miRNAs on post-transcriptional regulation of AFP gene, as well as the effects of HBV infection and icaritin in hepatoma cells. The results showed that miR-620, miR-1236 and miR-1270 could bind target sites in the range of 9–18 nt and 131–151 nt downstream of the stop codon in the AFP mRNA 3′-UTR to suppress the expression of AFP. Mutation of these target sites could reverse the effects of these miRNAs. Icaritin (10 μM) might reduce the stability and translational activity of AFP mRNA by increasing the expression levels of these mentioned miRNAs. HBV infection resulted in apparent decreases of these miRNAs and, consequently, increased AFP expression. The results indicated that miR-620, miR-1236 and miR-1270 are critical factors in the post-transcriptional regulation of AFP. Icaritin can counteract the effect of HBV. These findings will contribute to full understanding of the regulatory mechanism of AFP expression in hepatoma cells. And also it revealed a synergistic mechanism of HBV infection and elevation of AFP in the pathogenesis of HCC, as well as the potential clinical significance of icaritin on the therapy of HCC induced by HBV.

Effects of harmaline on cell growth of human liver cancer through the p53/p21 and Fas/FasL signaling pathways

The effects of harmaline on the viability and apoptosis of human liver carcinoma were investigated in vitro. HepG2 cells were treated with harmaline (0-10 µM), and the proliferation and apoptosis of HepG2 cells were investigated using an MTT assay and flow cytometry, respectively. The protein expression of cellular tumor antigen p53 (p53), cyclin-dependent kinase inhibitor 1 (p21), tumor necrosis factor receptor superfamily member 6 (Fas), Fas ligand (FasL) and caspase-8 was subsequently measured using western blotting. In addition, an ELISA was used to analyze caspase-8/3 activity. Harmaline significantly increased p53, p21, Fas and FasL protein expression in HepG2 cells. Additionally, treatment with harmaline significantly increased the expression of caspase-8 and caspase-8/3 activity. The results from the present study suggest that harmaline suppresses the viability, but induces the apoptosis, of human liver carcinoma cells through upregulation of the p53/p21 and Fas/FasL signaling pathways.

Changes of alpha-fetoprotein levels could predict recurrent hepatocellular carcinoma survival after trans-arterial chemoembolization

Background

There is paucity of information concerning whether AFP change is a predictor of prognosis for recurrent hepatocellular carcinoma (RHCC) patients after trans-arterial chemoembolization (TACE).

Methods

A total of 177 RHCC patients who received TACE as first-line therapy were retrospectively analyzed. The patients were classified into three groups according to their pre-TACE and post-TACE AFP levels (group A: AFP decreased, group B: AFP consistent normal, and group C: AFP increased). The recurrence to death survival (RTDS) and overall survival (OS) were estimated by the Kaplan-Meier method, and compared by the log-rank test. Multivariate analyses were performed to identify prognostic factors for OS and RTDS.

Results

There was no significant difference among the three groups concerning the baseline characteristics. The median overall survival (OS) was 74.5 months in group A (95% confidence interval (CI): 63.5, 85.6), 64.0 months in group B (95% CI: 52.3, 75.7) and 29.0 months in group C (95% CI: 24.1, 33.9; P<0.001). The median recurrence to death survival (RTDS) was 66.5 months (95% CI: 53.4, 79.6) in group A, 50.4 months (95% CI: 39.5, 61.4) in group B and 17.7 months (95% CI: 13.4, 22.1; P<0.001) in group C. Multivariate analysis revealed that tumor size at resection stage, tumor number at recurrent stage, cycles of TACE, mRECIST response and AFP change after TACE were significant independent risk factors for RTDS and OS.

Conclusions

AFP change could predict the prognoses of patients with RHCC who received trans-arterial chemoembolization, which may help clinicians make subsequent treatment decision.

Alpha fetoprotein antagonizes apoptosis induced by paclitaxel in hepatoma cells in vitro

Hepatocellular carcinoma (HCC) cell resistance to the effects of paclitaxel has not been adequately addressed. In this study, we found that paclitaxel significantly inhibited the viability of HLE, Bel 7402 and L-02 cells in a dose- and time-dependent manner. HLE cells and L-02 cells resisted the cytotoxicity of paclitaxel when transfected with pcDNA3.1-afp vectors. However, Bel 7402 cell sensitivity to paclitaxel was increased when transfected with alpha fetoprotein (AFP)-siRNA. Bel 7402 cell resistance to paclitaxel was associated with the expression of the “stemness” markers CD44 and CD133. Paclitaxel significantly inhibited growth and promoted apoptosis in HLE cells and L-02 cells by inducing fragmentation of caspase-3 and inhibiting the expression of Ras and Survivin, but pcDNA3.1-afp vectors prevented these effects. However, paclitaxel could not significantly promote the cleavage of caspase-3 or suppress the expression of Ras and Survivin in Bel 7402 cells. Silenced expression of AFP may be synergistic with paclitaxel to restrain proliferation and induce apoptosis, enhance cleavage of caspase-3, and suppress the expression of Ras and Survivin. Taken together, AFP may be an important molecule acting against paclitaxel-inhibited proliferation and induced apoptosis in HCC cells via repressing the activity of caspase-3 and stimulating the expression of Ras and Survivin. Targeted inhibition of AFP expression after treatment with paclitaxel is an available strategy for the therapy of patients with HCC.

Role of alpha-fetoprotein in hepatitis B virus-induced hepatocellular carcinoma: Prospect in clinical application

Mammalian alpha-fetoprotein (AFP) as a fetal specific alpha-globulin that has been used as a serum fetal defect/tumor marker for diagnosis and prediction of liver disease. Over the past decade, research indicates that AFP as an intracellular signal molecule is not only a biomarker but also interacts with hepatitis B virus (HBV) and hepatitis B virus protein x and plays multifarious roles in the development of hepatocellular carcinoma, especially in HBV-induced liver cancer.

GALNT14 genotype, α-fetoprotein and therapeutic side effects predict post-chemotherapy survival in patients with advanced hepatocellular carcinoma

In addition to targeted agents, chemotherapy is currently considered to be a treatment option for patients with advanced hepatocellular carcinoma (HCC); however, it is associated with severe side effects that may limit its clinical use. UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetyl-galactosaminyltransferase 14 (GALNT14) genotype was previously identified as a prognostic marker for HCC patients receiving 5-fluorouracil, mitoxantrone and cisplatin (FMP) combination chemotherapy. The present study aimed to assess clinical parameters and on-treatment side effects as effective predictors for favorable prognosis. A total of 118 patients with HCC receiving split-dose FMP were retrospectively enrolled. The clinical parameters, side effects and GALNT14 genotype were analyzed. The independent predictors for time-to-progression (TTP) and overall survival (OS) were assessed using Cox proportional hazards models. Following categorization, the Kaplan-Meier method was used to compare survival outcomes. Pretreatment α-fetoprotein (AFP) ≤2,800 ng/ml (median level), GALNT14 'TT' genotype, on-treatment leukopenia and absence of vomiting were identified as independent predictors of a favorable TTP (P=0.001, 0.035, 0.008 and 0.009, respectively) and OS (P=0.028, 0.006, 0.027 and 0.013, respectively). A total of 59 patients with AFP ≤2,800 ng/ml exhibited longer median TTP and OS (3.11 vs. 1.75 months, P<0.001; and 8.14 vs. 3.79 months, P<0.001, respectively). A total of 30 patients with the GALNT14 'TT' genotype exhibited longer median TTP and OS (3.11 vs. 2.11 months, P=0.014; and 5.75 vs. 3.93 months, P=0.001, respectively). Finally, 9 patients (9/118; 7.6%) with all four favorable factors exhibited the longest median TTP and OS (10.64 vs. 2.07 months, P=0.002; and 25.50 vs. 4.50 months, P<0.001, respectively). In conclusion, the AFP level and the GALNT genotype may be considered as pre-therapeutic predictors of a favorable response. When combined with on-treatment leukopenia and absence of vomiting, a subgroup of patients with excellent outcome may be identified.

Activation of cellular immunity and marked inhibition of liver cancer in a mouse model following gene therapy and tumor expression of GM-SCF, IL-21, and Rae-1

Background

Cancer is both a systemic and a genetic disease. The pathogenesis of cancer might be related to dampened immunity. Host immunity recognizes nascent malignant cells – a process referred to as immune surveillance. Augmenting immune surveillance and suppressing immune escape are crucial in tumor immunotherapy.

Methods

A recombinant plasmid capable of co-expressing granulocyte-macrophage colony- stimulating factor (GM-SCF), interleukin-21 (IL-21), and retinoic acid early transcription factor-1 (Rae-1) was constructed, and its effects determined in a mouse model of subcutaneous liver cancer. Serum specimens were assayed for IL-2 and INF-γ by ELISA. Liver cancer specimens were isolated for Rae-1 expression by RT-PCR and Western blot, and splenocytes were analyzed by flow cytometry.

Results

The recombinant plasmid inhibited the growth of liver cancer and prolonged survival of tumor-loaded mice. Activation of host immunity might have contributed to this effect by promoting increased numbers and cytotoxicity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL) following expression of GM-SCF, IL-21, and Rae-1. By contrast, the frequency of regulatory T cells was decreased, Consequently, activated CTL and NK cells enhanced their secretion of INF-γ, which promoted cytotoxicity of NK cells and CTL. Moreover, active CTL showed dramatic secretion of IL-2, which stimulates CTL. The recombinant expression plasmid also augmented Rae-1 expression by liver cancer cells. Rae-1 receptor expressing CTL and NK cells removed liver cancer.

Conclusions

The recombinant expression plasmid inhibited liver cancer by a mechanism that involved activation of cell-mediated immunity and Rae-1 in liver cancer.

Alpha-fetoprotein: a renaissance

Alpha-fetoprotein (AFP) is a major mammalian embryo-specific and tumor-associated protein that is also present in small quantities in adults at normal conditions. Discovery of the phenomenon of AFP biosynthesis in carcinogenesis by G. Abelev and Yu. Tatarinov 50 years ago, in 1963, provoked intensive studies of this protein. AFPs of some mammalian species were isolated, purified and physico-chemically and immunochemically characterized. Despite the significant success in study of AFP, its three-dimensional structure, mechanisms of receptor binding along with a structure of the receptor itself and, what is the most important, its biological role in embryo- and carcinogenesis remain still obscure. Due to difficulties linked with methodological limitations, research of AFP was to some extent extinguished by the 1990 s. However, over the last decade a growing number of investigations of AFP and its usage as a tumor-specific biomarker have been observed. This was caused by the use of new technologies, primarily, computer-based and genetic engineering approaches in studying of this very important oncodevelopmental protein. Our review summarizes efforts of different scientific groups throughout the world in studying AFP for 50 years with emphasis on detailed description of recent achievements in this field.

Lipiodolized transarterial chemoembolization in hepatocellular carcinoma patients after curative resection

PURPOSE

To explore the effect of lipiodolized transarterial chemoembolization (lip-TACE) in hepatocellular carcinoma (HCC) patients at different risk of recurrence after curative resection.

METHODS

One thousand nine hundred and twenty-four consecutive HCC patients who underwent curative resection were retrospectively analyzed. Patients who underwent resection only were classified into control group, while those received adjuvant lip-TACE were classified into intervention group. Patients were further stratified into 4 groups, that is, tumor ≤5 cm with low or high risk factors, as well as tumor >5 cm with low or high risk factors for recurrence. Tumor number and microscopic tumor thrombus were defined as risk factors for recurrence. The effect of adjuvant lip-TACE on early (<2 year) or late (≥2 year) recurrence was evaluated.

RESULTS

There was no significant difference in recurrence curve between intervention group and control group in each stratum. Adjuvant lip-TACE showed an overall survival benefit in patients with tumor >5 cm and presenting high risk factors, mainly for those with time to recurrence (TTR) <2 years after operation. For them, the median survival was 17 months in the intervention group and 11 months in the control group (P = 0.010). For patients who were confirmed to be recurrence-free at 2 years after operation, it had the negative effect for survival (HR = 1.75, P = 0.004).

CONCLUSION

Adjuvant lip-TACE had no preventive effect on recurrence, but may be of benefit to detect early recurrence.

Distinctions between clinicopathological factors and prognosis of alpha-fetoprotein negative and positive hepatocelluar carcinoma patients

Serum alpha-fetoprotein (AFP) is a significant marker for clinical diagnosis and prognosis evaluation in hepatocellular carcinoma (HCC) patients. However, some proportion of liver cancer patients are AFP-negative (AFP ≤20 ng/ml). In order to study the differences between clinicopathological factors and prognosis of alpha-fetoprotein negative and positive patients, a total of 114 cases (41 AFP-negative and 73 AFP-positive) were selected for our research. By systematically statistical analysis, the results demonstrated that compared with AFP-negative patients, AFP-positive examples were more likely to feature cirrhosis nodules, non-complete neoplasm capsules, and a poor Edmondson-steiner grade. Furthermore, AFP-negative patients demonstrated a favorable long-term prognosis. By univariate analysis and multivariate analysis with Cox's proportional hazards model, multiple tumors were found to be independent risk factors for worse survival of AFP negative patients; however, less tumor-free margins, multiple tumors and Edmondson-steiner grades III/IV, proved to be independent risk factors leading to a poor prognosis of AFP positive cases. Finally, we can infer that high levels of AFP signify a highly malignant tumor and unfavorable prognosis.

Transforming growth factor-beta signaling promotes hepatocarcinogenesis induced by p53 loss

Hepatocellular carcinoma (HCC) results from the accumulation of deregulated tumor suppressor genes and/or oncogenes in hepatocytes. Inactivation of TP53 and inhibition of transforming growth factor-beta (TGF-β) signaling are among the most common molecular events in human liver cancers. Thus, we assessed whether inactivation of TGF-β signaling, by deletion of the TGF-β receptor, type II (Tgfbr2), cooperates with Trp53 loss to drive HCC formation. Albumin-cre transgenic mice were crossed with floxed Trp53 and/or floxed Tgfbr2 mice to generate mice lacking p53 and/or Tgfbr2 in the liver. Deletion of Trp53 alone (Trp53(KO) ) resulted in liver tumors in approximately 41% of mice by 10 months of age, whereas inactivation of Tgfbr2 alone (Tgfbr2(KO) ) did not induce liver tumors. Surprisingly, deletion of Tgfbr2 in the setting of p53 loss (Trp53(KO) ;Tgfbr2(KO) ) decreased the frequency of mice with liver tumors to around 17% and delayed the age of tumor onset. Interestingly, Trp53(KO) and Trp53(KO) ;Tgfbr2(KO) mice develop both HCC and cholangiocarcinomas, suggesting that loss of p53, independent of TGF-β, may affect liver tumor formation through effects on a common liver stem cell population. Assessment of potential mechanisms through which TGF-β signaling may promote liver tumor formation in the setting of p53 loss revealed a subset of Trp53(KO) tumors that express increased levels of alpha-fetoprotein. Furthermore, tumors from Trp53(KO) mice express increased TGF-β1 levels compared with tumors from Trp53(KO) ;Tgfbr2(KO) mice. Increased phosphorylated Smad3 and ERK1/2 expression was also detected in the tumors from Trp53(KO) mice and correlated with increased expression of the TGF-β responsive genes, Pai1 and Ctgf.

CONCLUSION

TGF-β signaling paradoxically promotes the formation of liver tumors that arise in the setting of p53 inactivation.

Transforming growth factor-beta signaling promotes hepatocarcinogenesis induced by p53 loss

Hepatocellular carcinoma (HCC) results from the accumulation of deregulated tumor suppressor genes and/or oncogenes in hepatocytes. Inactivation of TP53 and inhibition of transforming growth factor-beta (TGF-β) signaling are among the most common molecular events in human liver cancers. Thus, we assessed whether inactivation of TGF-β signaling, by deletion of the TGF-β receptor, type II (Tgfbr2), cooperates with Trp53 loss to drive HCC formation. Albumin-cre transgenic mice were crossed with floxed Trp53 and/or floxed Tgfbr2 mice to generate mice lacking p53 and/or Tgfbr2 in the liver. Deletion of Trp53 alone (Trp53(KO) ) resulted in liver tumors in approximately 41% of mice by 10 months of age, whereas inactivation of Tgfbr2 alone (Tgfbr2(KO) ) did not induce liver tumors. Surprisingly, deletion of Tgfbr2 in the setting of p53 loss (Trp53(KO) ;Tgfbr2(KO) ) decreased the frequency of mice with liver tumors to around 17% and delayed the age of tumor onset. Interestingly, Trp53(KO) and Trp53(KO) ;Tgfbr2(KO) mice develop both HCC and cholangiocarcinomas, suggesting that loss of p53, independent of TGF-β, may affect liver tumor formation through effects on a common liver stem cell population. Assessment of potential mechanisms through which TGF-β signaling may promote liver tumor formation in the setting of p53 loss revealed a subset of Trp53(KO) tumors that express increased levels of alpha-fetoprotein. Furthermore, tumors from Trp53(KO) mice express increased TGF-β1 levels compared with tumors from Trp53(KO) ;Tgfbr2(KO) mice. Increased phosphorylated Smad3 and ERK1/2 expression was also detected in the tumors from Trp53(KO) mice and correlated with increased expression of the TGF-β responsive genes, Pai1 and Ctgf.

CONCLUSION

TGF-β signaling paradoxically promotes the formation of liver tumors that arise in the setting of p53 inactivation.

Differential effects of vitamin K1 on AFP and DCP levels in patients with unresectable HCC and in HCC cell lines

PURPOSE

DCP is a useful HCC tumor marker, which reflects a defect in vitamin K metabolism. We tested the hypothesis that vitamin K treatment of HCC patients might suppress this marker and possibly AFP also.

EXPERIMENTAL DESIGN

HCC patients who had both elevated AFP and DCP were included. A phase I cohort was treated with escalating vitamin K1 intravenous weekly doses and a 27-patient phase II cohort was then treated with a fixed oral daily dose.

RESULTS

A maximum tolerated dose was not reached up to 100-fold the normal vitamin K1 dose. No toxicities were found up to 1,000 mg/infusion. In the phase II cohort, 93% of patients had tumor marker responses by decreased DCP levels, but only 22% had responses by decreased AFP levels. CT scans showed 11% of patients had PRs, 59% had stable tumors and 29.6% had tumor progression. Mechanism studies showed that vitamin K1 induced phosphorylation of JNK and c-Jun and caspase-mediated apoptosis.

CONCLUSIONS

Vitamin K1 was non-toxic at high doses, strongly inhibited plasma DCP levels, but weakly suppressed AFP levels. The results provide evidence that the two tumor markers are not directly linked and that DCP levels may not reflect HCC cell growth, as DCP levels were decreased in patients without AFP change, and were suppressed in vitro at 1% of the vitamin K1 concentration needed to inhibit AFP.

Risk factors for residual tumor after resection of hepatocellular carcinoma

AIM: To identify the clinicopathological risk factors correlated with residual tumor in hepatocellular carcinoma (HCC) patients after resection.

METHODS: From January 2001 to April 2007, 766 HCC patients who had undergone resection were included in this research. Lipiodol angiography was performed within 2 mo after surgery and followed by post-Lipiodol computed tomography (CT) 4 wk later for all 766 patients to monitor tumor in the remnant liver. Tumor detected within the first 3-mo postoperative period was defined as residual tumor. Patients were divided into 2 groups: disease or disease-free within the first 3 mo after surgery. Risk factors for residual tumor were investigated among various clinicopathological variables.

RESULTS: A total of 63 (8.22%) patients were found to have residual tumor after surgery. Three independent factors associated with residual tumor were identified by multivariate analysis: preoperative serum α -fetoprotein (AFP) level [odds ratio (OR) = 1.68 (95% confidence interval (CI): 1.20-2.36)], tumor size [OR = 1.73 (95% CI: 1.29-2.31)] and microvascular invasion [OR = 1.91 (95% CI: 1.12-3.24)].

CONCLUSION: Residual tumor is related to AFP level, tumor size and microvascular invasion. Patients at high risk should undergo closer follow-up and could be candidates for multimodality therapy.

Serum alpha-fetoprotein levels during and after interferon therapy and the development of hepatocellular carcinoma in patients with chronic hepatitis C

The association between serum alpha-fetoprotein (AFP) levels during and after interferon (IFN) therapy and the development of hepatocellular carcinoma (HCC) was evaluated in patients with chronic hepatitis C (CHC). A total of 263 patients treated by IFN with or without ribavirin were enrolled in the study. Serum AFP levels during and after IFN therapy were investigated retrospectively, and statistical analysis was performed to identify the factors associated with HCC development. During IFN therapy, serum AFP levels significantly decreased, regardless of virologic response to treatment. Increased serum AFP levels (>or=10 ng/ml) at the end of IFN therapy (EOT) was a close-to-significant variable affecting the development of HCC (P = 0.057), and a significantly higher cumulative incidence of HCC was seen in patients with increased serum AFP levels at EOT (P = 0.021). Serum AFP level at EOT is a possible predictor of HCC in CHC patients after IFN therapy.

Transformation of human liver L-O2 cells mediated by stable HBx transfection

AIM

To explore the mechanism of hepatocarcinogenesis associated with the hepatitis B virus X protein (HBx), we investigated the role of HBx in transformation using human liver L-O2 cells stably transfected with HBx as a model.

METHODS

Plasmids encoding HBx were stably transfected into immortalized human liver L-O2 cells and rodent fibroblast NIH/3T3 cells. The expression of alfa-fetoprotein (AFP), c-Myc, HBx, and survivin in the engineered cells was examined by Western blotting. The malignant phenotype of the cells was demonstrated by anchorage-independent colony formation and tumor formation in nude mice. RNA interference assays, Western blotting, luciferase reporter gene assays and flow cytometry analysis were performed. The number of centrosomes in the L-O2-X cells was determined by gamma-tubulin immunostaining. The effect of HBx on the transcriptional activity of human telomerase reverse transcriptase (hTERT) and hTERT activity in L-O2-X cells and/or 3T3-X cells was detected by the luciferase reporter gene assay and telomerase repeat amplification protocol (TRAP).

RESULTS

Stable HBx transfection resulted in a malignant phenotype in the engineered cells in vivo and in vitro. Meanwhile, HBx was able to increase the transcription of the NF-kappaB, AP-1, and survivin genes and to upregulate the expression levels of c-Myc and survivin. Abnormal centrosome duplication and activated hTERT were responsible for the transformation.

CONCLUSION

Stable HBx transfection leads to genomic instability of host cells, which is responsible for hepatocarcinogenesis; meanwhile, transactivation by the HBx protein contributes to the development of hepatocellular carcinoma (HCC). The L-O2-X cell line is an ideal model for investigating the mechanism of HBx-mediated transformation.

Immunotherapy for liver tumors: present status and future prospects

Increasing evidence suggests that immune responses are involved in the control of cancer and that the immune system can be manipulated in different ways to recognize and attack tumors. Progress in immune-based strategies has opened new therapeutic avenues using a number of techniques destined to eliminate malignant cells. In the present review, we overview current knowledge on the importance, successes and difficulties of immunotherapy in liver tumors, including preclinical data available in animal models and information from clinical trials carried out during the lasts years. This review shows that new options for the treatment of advanced liver tumors are urgently needed and that there is a ground for future advances in the field.

Silencing alpha-fetoprotein expression induces growth arrest and apoptosis in human hepatocellular cancer cell

The expression of alpha-fetoprotein (AFP), a tumor-associated antigen, is silenced in normal adult hepatocyte but reactivated in human hepatocellular carcinoma (HCC). To investigate the roles of AFP in the regulation of cell growth, we silenced AFP expression in the HCC cell line Huh7 by transfection of specific Stealth RNAi. After the transfection for 48 h, the expression of AFP gene was almost abolished, the cell proliferation was inhibited by 46.15%, and the number of cells undergoing early apoptosis was significantly increased to 63.93%. Inhibition of AFP expression also resulted in an increased in Bax/Bcl-2 ratio, the release of cytochrome c from mitochondria and activation of caspase-3. The results suggest that AFP may positively regulate cell proliferation by enhancing the apoptosis resistance via dysfunction of the p53/Bax/cytochrome c/caspase-3 signaling pathway in AFP-producing HCC cell line. As such, the knockdown of AFP gene should be further investigated in vivo as a novel approach to HCC treatment.

Clinical significance of alpha-fetoprotein: involvement in proliferation, angiogenesis, and apoptosis of hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma is one of the most common cancers. alpha-Fetoprotein is strongly expressed in most patients with hepatocellular carcinoma, and high levels of alpha-fetoprotein expression have been reported as an independent prognostic factor. However, there have been few reports on the reasons for poor prognosis.

METHODS

We analyzed the correlation between serum alpha-fetoprotein levels and clinicopathological findings in 37 hepatocellular carcinoma patients undergoing curative surgery. alpha-Fetoprotein mRNA expression in tissue samples was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR), while protein expression was assessed by immunohistochemistry. To assess the mechanistic correlations between alpha-fetoprotein and tumor progression, we further analyzed cell proliferation (Ki-67), angiogenesis (CD34), and apoptosis (TdT-mediated dUTP-biotin nick end labeling [TUNEL] assay).

RESULTS

Post-operative serum alpha-fetoprotein levels were correlated with disease-free and overall survival, and were an independent prognostic factor for survival. alpha-Fetoprotein expression, as assessed by immunohistochemistry, was strong and heterogeneous in hepatocellular carcinoma. Control livers did not express alpha-fetoprotein and there was weak expression of alpha-fetoprotein in adjacent regions in hepatocellular carcinoma patients. The Ki-67 labeling index in the high serum alpha-fetoprotein cases was significantly higher than in alpha-fetoprotein-negative cases (P = 0.042). The alpha-fetoprotein-positive cases also showed a significantly higher microvessel density than alpha-fetoprotein-negative cases (P = 0.035), whereas hepatocellular carcinoma without alpha-fetoprotein overexpression had a higher apoptotic index when compared to hepatocellular carcinoma with alpha-fetoprotein overexpression (P = 0.033).

CONCLUSION

These results indicate that the poor prognosis associated with high alpha-fetoprotein is due to high cell proliferation, high angiogenesis, and low apoptosis.

Targeting alpha-fetoprotein represses the proliferation of hepatoma cells via regulation of the cell cycle

BACKGROUND

AFP is a biomarker for primary liver cancer, yet little is known about its effect in the pathogenesis of hepatoma. We examined how AFP modulates the proliferation of hepatoma cells.

METHODS

Recombinant adenovirus expressing siRNA against AFP was created. The repression of cell proliferation in vitro and growth of hepatoma in vivo were examined by colony formation assay and tumor xenograft in SCID mice, respectively. Cell cycle was assayed by flow cytometry. Expression profile was determined by microarrays.

RESULTS

siRNA targeting reduced expression of AFP specifically and markedly inhibited the proliferation of hepatoma cells. Local treatment using Adv-AFPsiRNA caused significant repression of the growth of hepatoma derived HepG2 cells in xenograft in SCID mice. Knockdown of AFP resulted in an obvious delay in the G(1)/S transition of cell cycle, but did not affect apoptosis in HepG2 cells. Some genes related to the cell cycle, including SKP2, Cyclin D1, Csk and EBAG9 were identified.

CONCLUSIONS

The endogenous AFP is a critical determinant of the growth of hepatoma cells, which functions by regulating the cell cycle. This study suggests that targeting of AFP with siRNA could be a potential therapeutic approach for hepatoma.

Down-regulation of beta-centractin might be involved in dendritic cells dysfunction and subsequent hepatocellular carcinoma immune escape: a proteomic study

AIMS

Proteomic study was used to clarify the mechanism of hepatocellular carcinoma (HCC) immune escape concerning Dendritic cells (DCs') dysfunction and their association with HCC invasion.

METHODS

Human peripheral blood mononuclear cells (PBMCs) derived DCs from healthy donors were pulsed with soluble cell lysates prepared from different metastatic potential human HCC cell lines. The total protein of these DCs was analyzed by two-dimensional electrophoresis and Electro-Spray Mass Spectrometry. The allostimulatoy capacity and phenotype of these DCs were also evaluated. The clinical significance of beta-centractin, one of the largest quantitative changed spot, down-regulation in DCs was further evaluated in autologous PBMCs derived DCs pulsed with auto-tumor lysates in 26 HCC patients.

RESULTS

The expression of beta-centractin was found to be considerably lower either in DCs pulsed with HCCLM6 (high metastatic potential HCC cell line) lysates, accompanied by down-regulation of CD86 molecule and impaired allostimulatory capacity, than those of DCs pulsed with lysates from HCC cell lines with low or without metastatic potential or in DCs pulsed with lysates from HCC with invasiveness than those without invasiveness.

CONCLUSIONS

The down-regulation of beta-centractin in DCs pulsed with high metastatic potential HCC lysates might associate with DCs dysfunction and HCC invasiveness.

High level of expression of alpha-fetoprotein receptor in gastric cancers

The expression of the receptor for alpha-fetoprotein (AFP-R) was examined immunohistochemically in 47 cancer and 14 benign human gastric tissues. Rabbit polyclonal antibody against human AFP-R was used for immunohistochemical staining. Thirty-four of the 47 cancer tissues expressed AFP-R showing granular or reticular staining on the cancer cell surface, while only 2 of 61 control cases (14 benign gastric tissues and 47 nonmalignant tissues adjacent to cancer) showed faint and homogeneous staining in the cytoplasm of noncancerous cells. There was a significant difference in staining intensity between the cancerous and noncancerous groups. However, no statistically significant difference in staining intensity was found among the groups of well-differentiated, moderately differentiated and poorly differentiated adenocarcinomas. On the other hand, the staining intensity of signet ring cell carcinoma was significantly weaker than that of the three adenocarcinoma groups. The high level of AFP-R expression in gastric cancers may allow the use of AFP-R as a new clinically useful marker of gastric cancer in the tissue level.

Serum tumor markers for detection of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent malignant tumors and is the second most common cause of cancer death in China. Therefore, it is very important to detect this disease and the recurrence at its earlier period. Serum tumor markers, as the effective method for detecting hepatocellular carcinoma for a long time, could be divided into 4 categories: oncofetal antigens and glycoprotein antigens; enzymes and isoenzymes; genes; and cytokines. Serum alpha fetoprotein (AFP) is the most widely used tumor marker in detecting patients with hepatocellular carcinoma, and has been proven to have capability of prefiguring the prognosis. However, it has been indicated that AFP-L3 and DCP excel AFP in differentiating hepatocellular carcinoma from nonmalignant hepatopathy and detecting small hepatocellular carcinoma. Some tumor markers, such as human cervical cancer oncogene and human telomerase reverse transcriptase mRNA, have also been indicated to have higher accuracies than AFP. Furthermore, some other tumor markers, such as glypican-3, gamma-glutamyl transferase II, alpha-l-fucosidase, transforming growth factor-beta1, tumor-specific growth factor, have been indicated to be available supplementaries to AFP in the detection. AFP mRNA has been shown to correlate with the metastasis and recurrence of HCC, and it may be the most useful marker to prefigure the prognosis. Some other markers, such as gamma-glutamyl transferase mRNA, vascular endothelial growth factor, and interleukin-8, could also be used as available prognostic indicators, and the simultaneous determination of AFP and these markers may detect the recurrence of HCC at its earlier period.