Expression Of Cancer-testis Antigens SSX-2 And SSX-5 In Tissue And Peripheral Blood Of The Patients With Hepatocellular Carcinoma

Objective Cancer-testis antigens( CTA) are a family of many kinds of tumor-specific antigens, and they express merely in testis and many kinds of tumors . SSX family belongs to CTA . The aim of our research is to investigate the expression of SSX-2 and SSX-5 mRNA in the tissue and peripheral blood of the patients with hepatocellular carcinoma (HCC) ,to assure the relation between the expression and kinds of clinical indexes , and to evaluate the possibility for the targets of specific immunotherapy to HCC and the markers as the adjuvant diagnostic tools and of detecting the metastasis, recurrence and prognosis for HCC patients . Methods One-step RT-PCR was used to investigate the expression of the SSX-2 and SSX-5 mRNA in the HCC tissues , corresponding adjacent non-HCC tissues and peripheral bloods of 25 patients with HCC . In addition , 12 samples of cirrositic tissues and 10 normal tissues were examined using the same method. The relation between the results and the kinds of clinical characters ,for example ,AFP, HBSAg, diameter of the tumor, TNM staging, and so on,was analysed. Result OF the 25 cases of HCC tissues, SSX-2 and SSX-5 mRNA was detectable in 32%(8/25) and 48%(12/25) of HCC tissues respectively, while none of the two genes is detectable in the corresponding adjacent non-HCC tissues. At least one gene mRNA was found in 52%(13/25) of HCC tissues. The positive co-expression of the two genes was found in 28%(7/25) of HCC tissues . In the peripheral bloods of the 25 patients with HCC, the positive expression rate of the SSX-2 and SSX-5 mRNA was 16%(4/25) and 24%(6/25) respectively. The positive expression of one of the two genes and both of the two genes was found in 40%(10/25) and 0(0/25) respectively. Of 12 cirrosis patients and other 10 non-tumor patients, SSX-2 and SSX-5 mRNA was not detectable in both liver tissue and peripheral blood. The DNA sequence confirmed that the RT-PCR products were truly target cDNA. No relationship was found between the expression of the two genes and clinical characters such as age, sex, tumor size, serum a -fetoprotein level and infection of hepatitis virus (P>0.05). Of the 9 patients with normal serum a -fetoprotein (<20ng/L) , SSX-5 gene was observed in 3 patients' peripheral blood. Two patients with positive SSX-5 gene in peripheral blood was recurrent within 6 months after resection of HCC. Conclusion SSX-2 and SSX-5 mRNA were expressed with a high frequence and specificity in HCC and their products may be a new potential promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of the two genes in HCC tissues provides a possibility as the polyvalent vaccinations for HCC. The positive expression of the SSX-2 and SSX-5 genes in the peripheral blood only exist in the positive samples of the two genes in the HCC tissues. The high-specifity of expression may be a way to diagnose HCC and to evaluate the metastasis and recurrence of HCC after resection.