Cancer-testis and melanocyte-differentiation antigen expression in malignant glioma and meningioma

Identification of well-defined glioma-specific antigens is a crucial and necessary step in developing immunotherapy for glioblastoma multiforme (GBM). In this study, we analyzed the composite expression of cancer-testis antigens (CTA) and melanocyte-differentiation antigens (MDA) in malignant glioma tissue and primary glioma cell lines and compared them with normal brain specimens and meningioma. CTA and MDA expression was assessed by the reverse transcription-polymerase chain reaction. The following primers were analyzed for CTA: LAGE-1, NY-ESO-1, MAGE-1, MAGE-3, MAGE-4, MAGE-10, CT-7, CT-10, HOM-MEL 40, BAGE, and SCP-1; and for MDA: tyrosinase, gp100, MELAN-A/MART-1, and TRP-2. The expression level was determined by ethidium bromide-stained agarose gel. Among malignant glioma tissue, the highest CTA and MDA expression rates were found for MAGE-3 (22%), MAGE-1 (16%), CT-7 (11%), gp100 (40%), and TRP-2 (29%). Among primary glioma cell lines, the highest levels of expression were: CT-10 (38%), gp100 (100%), and TRP-2 (31%). NY-ESO-1 was the only CTA demonstrated and seen in 12% of meningioma tissue specimens. TRP-2 and gp100 were expressed in 65% and 38% of meningioma tissue, respectively; gp100 and TRP-2 were expressed in 100% and 50% of meningioma cell lines. Of the nine normal brain specimens, all samples tested positive for TRP-2. All other CTA and MDA tested negative in normal brain. We conclude that CTA and MDA demonstrate low-to-variable levels of expression within GBM. However, two CTA (MAGE-1 and MAGE-3) and one MDA (gp100) may be considered candidate antigens based on their restricted expression in GBM. These results will greatly accelerate the development of novel, specific immunotherapeutic strategies.