Alternative titles; symbols
HGNC Approved Gene Symbol: SAGE1
Cytogenetic location: Xq26.3 Genomic coordinates (GRCh38): X:135,893,716-135,913,062 (from NCBI)
Several classes of tumor antigens recognized by cytolytic T lymphocytes (CTLs) have been identified, including an important class encoded by genes that are activated in tumors. These genes belong to the MAGE (e.g., MAGEA1; 300016), BAGE (605167), GAGE (e.g., GAGE1; 300594), and other families. They are all expressed in tumors of different histologic types but not in normal tissues, except for spermatogenic cells and, for some, placenta. The antigens appear to be strictly tumor-specific, because the spermatogenic cells that express these tumors do not express HLA molecules and are therefore incapable of presenting antigens to T cells. As these genes are expressed in a large proportion of tumors of various histologic types, they may be excellent sources of antigens for cancer immunotherapy.
To identify genes with tumor-specific expression, Martelange et al. (2000) applied a cDNA subtraction approach, i.e., representational difference analysis, to a human rhabdomyosarcoma cell line. They obtained 2 cDNAs that appeared to be tumor specific and named the corresponding genes SAGE and HAGE (606286), because they had the same pattern of expression as genes of the MAGE family. SAGE encodes a putative 904-amino acid protein that contains 15 repeated motifs of 47 amino acids. Northern blot analysis detected expression of a 3.5-kb SAGE transcript mainly in bladder carcinoma, lung carcinoma, and head and neck carcinoma; no expression was detected in normal tissue except for testis.
By radiation hybrid analysis, Martelange et al. (2000) mapped the SAGE1 gene to Xq28, near the MAGEA genes. They provided, in their Figure 5, a diagram of the localization of SAGE1 and other tumor-specific genes on the X chromosome.
See 300016 for a discussion of the high frequency of genes on the X chromosome encoding proteins with the MAGE domain as well as other cancer-testis antigen genes (Ross et al., 2005).
Martelange, V., De Smet, C., De Plaen, E., Lurquin, C., Boon, T. Identification on a human sarcoma of two new genes with tumor-specific expression. Cancer Res. 60: 3848-3855, 2000. [PubMed: 10919659]
Ross, M. T., Grafham, D. V., Coffey, A. J., Scherer, S., McLay, K., Muzny, D., Platzer, M., Howell, G. R., Burrows, C., Bird, C. P., Frankish, A., Lovell, F. L., and 270 others. The DNA sequence of the human X chromosome. Nature 434: 325-337, 2005. [PubMed: 15772651] [Full Text: https://doi.org/10.1038/nature03440]