Expression of MHC class I, MHC class II, and cancer germline antigens in neuroblastoma

Abstract

Background: Neuroblastoma is the most common solid extracranial tumor in childhood, still with poor survival rates for metastatic disease. Neuroblastoma cells are of neuroectodermal origin and express a number of cancer germline (CG) antigens. These CG antigens may represent a potential target for immunotherapy such as peptide-based vaccination strategies.

Objective: The purpose of this study was to analyze the presence of MAGE-A1, MAGE-A3/A6, and NY-ESO-1 on an mRNA and protein level and to determine the expression of MHC class I and MHC class II antigens within the same tumor specimens.

Methods: A total of 68 tumors were available for RT-PCR, and 19/68 tumors were available for immunohistochemical (IHC) analysis of MAGE-A1, MAGE-A3/A6, and NY-ESO-1. In parallel, the same tumors were stained with a panel of antibodies for MHC class I and MHC class II molecules.

Results: Screening of 68 tumor specimens by RT-PCR revealed expression of MAGE-A1 in 44%, MAGE-A3/A6 in 21%, and NY-ESO-1 in 28% of cases. Immunohistochemistry for CG antigens of selected tumors showed good agreement between protein and gene expression. However, staining revealed a heterogeneous expression of CG antigens. None of the selected tumors showed MHC class I or MHC class II expression.

Conclusions: mRNA expression of MAGE-A1, MAGE-A3/A6, and NY-ESO-1 is congruent with the protein expression as determined by immunohistochemistry. The heterogeneous CG-antigen expression and the lack of MHC class I and II molecules may have implications for T-cell-mediated immunotherapy in neuroblastoma.

Fig. 1

IHC for CG antigens. a, b Staining with mAb ES121 for NY-ESO-1: a patient no. 11, poorly differentiated neuroblastoma, 250-fold; b patient no. 17, ganglioneuroblastoma, immunoreactivity of mature and immature ganglion cells and no staining of the neuroblasts in the poorly differentiated areas (inlet), 400-fold. c, d Reactivity against mAbM454 for MAGE-A1: c patient no. 11, neuroblasts showing a strong staining intensity (4+), 250-fold; d patient no. 2, focal staining in differentiating neuroblasts, 400-fold. e, f Reactivity against mAb for M3H67 for MAGE-A3/A6: e patient no. 11, 4+, 250-fold; f patient no. 13, 2+, 250-fold.

Fig. 2

Staining for MHC class I expression in neuroblastoma (patient no. 15). Top staining with mAbW6/32 for HLA-A, HLA-B, HLA-C expression; center mAb GRH1 against β2-m; bottom mAb HC-10 against the MHC heavy chain.