Expression of the MAGE gene family in human hepatocellular carcinoma

Expression of cancer-testis antigens SSX-1 and NY-ESO-1 mRNA in hepatocellular carcinoma and its clinical significance

AIM: To investigate the expression of SSX-1 and NY-ESO-1 mRNA in hepatocellular carcinoma (HCC) and their clinical significances.

METHODS: The expression of SSX-1 and NY-ESO-1 mRNA were detected in the cancer tissues, the corresponding cancer-adjacent tissues and the peripheral blood of 26 patients with HCC as well as of 20 controls by reverse transcription polymerase chain reaction (RT-PCR). A randomized sample of the RT-PCR products was selected for DNA sequencingto examine the reliability of results.

RESULTS: The positive rates of SSX-1 and NY-ESO-1 mRNA expression were 61.5%(16/26) and 11.5% (3/26), respectively, in cancer tissues, and they were 46.2%(12/26) and 3.8%(1/26) in the peripheral blood. HCC patients, whose peripheral blood expressed SSX-1 or NY-ESO-1 mRNA, also expressed the same gene in their cancer tissues. SSX-1 and NY-ESO-1 mRNA were not expressed in cancer-adjacent tussues, and tissues and peripheral blood of the controls. DNA sequencing confirmed that the RT-PCR products were the target cDNA. No significant relationship was found between the expression of SSX-1 and NY-ESO-1 and the clinical indicators such as age, gender, tumor size, extent of differentiation, serum a-fetoprotein (AFP) level and infection of hepatitis B virus (P>0.05). However, in 37.5% patients with normal serum AFP (<20 ng/L), specific expression of SSX-1 mRNA was observed. The short-term recurrent rate was 50%(4/8) in patients whose peripheral blood expressed SSX-1 mRNA, while the rate in patients with no SSX-1 mRNA expression was 25%(3/12).

CONCLUSION: SSX-1 and NY-ESO-1 are expressed with a high specificity in HCC, and they can be used as the targets for specific immunotherapy of HCC. The combination of SSX-1 mRNA and AFP detection can help to improve the accuracy of diagnosis for HCC. The expression of SSX-1mRNA may be used as an indicator for reccurrence, metastesis and prognosis of HCC.

Prediction of HLA-A2-restricted CTL epitope specific to HCC by SYFPEITHI combined with polynomial method

AIM: To predict the HLA-A2-restricted CTL epitopes of tumor antigens associated with hepatocellular carcinoma (HCC).

METHODS: MAGE-1, MAGE-3, MAGE-8, P53 and AFP were selected as objective antigens in this study for the close association with HCC. The HLA-A*0201 restricted CTL epitopes of objective tumor antigens were predicted by SYFPEITHI prediction method combined with the polynomial quantitative motifs method. The threshold of polynomial scores was set to -24.

RESULTS: The SYFPEITHI prediction values of all possible nonamers of a given protein sequence were added together and the ten high-scoring peptides of each protein were chosen for further analysis in primary prediction. Thirty-five candidates of CTL epitopes (nonamers) derived from the primary prediction results were selected by analyzing with the polynomial method and compared with reported CTL epitopes.

CONCLUSION: The combination of SYFPEITHI prediction method and polynomial method can improve the prediction efficiency and accuracy. These nonamers may be useful in the design of therapeutic peptide vaccine for HCC and as immunotherapeutic strategies against HCC after identified by immunology experiment.

Expression of cancer-testis antigens in hepatocellular carcinoma

AIM: To investigate the expression of cancer-testis (CT) antigens MAGE-1, SSX-1 ,CTp11 and HCA587 genes in hepatocellular carcinoma (HCC) and the possibility of applying these antigens as targets for specific immunotherapy for HCC.

METHODS: Expression levels of MAGE-1, SSX-1, CTp11 and HCA587 mRNA were detected with reverse transcription polymerase chain reaction (RT-PCR) in HCC tissues and corresponding adjacent non-cancerous tissues from 105 HCC patients, 40 samples of cirrhosis and normal liver tissues. Genes of five samples with positive PCR results were sequenced.

RESULTS: Of 105 HCC tissues, MAGE1, SSX-1 ,CTp11 and HCA587 mRNA expressions were detectable in 75.2% (79/105), 72.4% (76/105), 62.9% (66/105) and 56.2% (59/105) of HCC samples, respectively. About 93.3% (98/105), 72.4% (76/105), 48.6% (51/105) and 37.1% (39/105) of HCC tissues positively expressed at least one, two, three, and four members of CT antigens, respectively. Conversely, only SSX-1 could be detectable in 2.9% (3/105) of the corresponding adjacent non-HCC tissues in which no metastatic lesion was found. Of the latter 3 patients, biopsy samples far from tumor were obtained in 2 patients and RT-PCR indicated no expression of SSX-1 mRNA in these two samples. In addition, none of 40 samples of cirrhotic and normal liver tissues expressed CT antigen gene mRNA. DNA sequences confirmed that the RT-PCR products were true target cDNA. No relationship was found between expression of CT antigens and clinico pathological indicators such as age, gender, tumor size, degree of tumor differentiation, serum α-fetoprotein level and infection of hepatitis B virus or hepatitis C virus (P > 0.05).

CONCLUSION: CT antigens genes (MAGE-1, SSX-1, CTp11 and HCA587) are expressed with high percentage and specificity in HCC and their products are promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of multiple members of CT antigens in HCC provides possibility of polyvalent vaccinations for HCC.

Hepatocellular carcinoma--cause, treatment and metastasis

In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses (HBV and HCV) and dietary aflatoxin intake remain the major causative factors of HCC. Surgery plays a major role in the treatment of HCC, particularly for small HCC. Down-staging unresectable huge HCC to smaller HCC and followed by resection will probably be a new approach for further study. Liver transplantation is indicated for small HCC, however, some issues remain to be solved. Different modes of regional cancer therapy for HCC have been tried. Systemic chemotherapy has been disappointing in the past but the future can be promising. Biotherapy, such as cytokines, differentiation inducers, anti-angiogenic agents, gene therapy and tumor vaccine will probably play a role, particularly in the prevention of tumor recurrence. HCC invasiveness is currently the major target of study. Tremendous works have been done at the molecular level, which will provide clues for biomarker of HCC progression as well as targets for intervention.