Expression of Cancer/Testis Tumor Associated Antigens in Cervical Squamous Cell Carcinoma

We investigated the expression of tumor-associated antigens (TAA) of the cancer/testis (C/T) gene family in cervical squamous cell carcinomas. First, we focused on the HeLa cervical cancer derived cell line, and we found that it expresses MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A12, GAGE-3/6, LAGE-1, and PRAME genes, encoding defined C/T TAA. In contrast, no expression of MAGE-A10, BAGE, GAGE-1/2, or NY-ESO-1 genes was observed. Corresponding gene products could also be detected by immunoblotting and immunocytochemistry, taking advantage of monoclonal antibodies recognizing discrete TAA. Capitalizing on these data, a monoclonal antibody predominantly recognizing MAGE-A4 TAA in paraffin-embedded sections (57B) was used to investigate the C/T gene expression in clinical tumor samples. A group of 60 patients was studied, and 57B positivity was detectable to different extents in 33% of the cases (20/60). In 13 of them (21%), staining of over 50% of the tumor cells was evident, whereas healthy cells always scored negative. Remarkably, MAGE-A4 expression was significantly (p < 0.05) more frequently detectable in poorly differentiated tumors (8/13) than in well-differentiated or moderately differentiated cancers (3/15 and 9/32, respectively) and in stage FIGO II as compared with stage FIGO Ib tumors (12/23 and 5/24, respectively, p = 0.04). Interestingly, staining was mostly nuclear in well-differentiated tumors, but involved both nuclei and cytoplasm in less differentiated cancers. Positivities of comparable frequency were also detectable in a smaller series of specimens upon staining with MAGE-A1- or NY-ESO-1/LAGE-1-specific reagents. Considering the high tumor specificity of C/T TAA, our data provide the rationale for the design of immunotherapy procedures targeting these antigens in cervical cancers.