Cancer-germline genes (CGGs) code for immunogenic antigens that are present in various human tumors and can be targeted by
immunotherapy. Their expression has been studied in a wide range of human tumors in adults. We measured the expression of
12 CGGs in pediatric brain tumors, to identify targets for therapeutic cancer vaccines. Real Time PCR was used to quantify
the expression of genes
MAGE-A1,
MAGE-A2,
MAGE-A3,
MAGE-A4,
MAGE-A6,
MAGE-A10,
MAGE-A12,
MAGE-C2,
NY-ESO-1 and
GAGE-1,
2,
8 in 50 pediatric brain tumors of different histological subtypes. Protein expression was examined with immunohistochemistry.
Fifty-five percent of the medulloblastomas (
n = 11), 86% of the ependymomas (
n = 7), 40% of the choroid plexus tumors (
n = 5) and 67% of astrocytic tumors (
n = 27) expressed one or more CGGs. Immunohistochemical analysis confirmed qPCR results. With exception of a minority of tumors,
the overall level of CGG expression in pediatric brain tumors was low. We observed a high expression of at least one CGG in
32% of the samples. CGG-encoded antigens are therefore suitable targets in a very selected group of pediatric patients with
a brain tumor. Interestingly, glioblastomas from adult patients expressed CGGs more often and at significantly higher levels
compared to pediatric glioblastomas. This observation is in line with the notion that pediatric and adult glioblastomas develop
along different genetic pathways.
Keywords Brain tumor - Pediatrics - qPCR - MAGE - NY-ESO-1 - Immune target