Immunohistochemical staining of medulloblastomas. Medulloblastoma samples were stained with monoclonal antibodies (mAbs) MA454 (to MAGEA1), M3H67 (to MAGEA3/6), 57B (to MAGEA4), CT7-33 (to MAGEC1), CT10#5 (to MAGEC2), and #23 (to GAGE). Low power view of weak mAb MA454 staining (A) of case #10, with transition of immunopositive and negative (*) tumor areas and cytoplasmic staining (B) of tumor cells. Area with nuclear mAb M3H67 staining of most tumor cells (C) and only occasional nuclear immunoreactivity in a different area (D) of medulloblastoma case #5. Low power view of immunostaining with mAb 57B in medulloblastoma #10, with heterogeneously positive area (E) displaying exclusive nuclear immunoreactivity (F). Low power view of medulloblastoma #17, with foci of CT7-33 staining (G) resembling focal accumulations of tumor cells (H), here with mostly cytoplasmic and only occasional nuclear immunostaining (thick black arrows). Nuclear immunostaining of scattered tumor cells (I) with mAb CT10#5, forming small immunopositive foci in medulloblastoma case #17 (J). Overview of mAb #23 immunopositive area in a mostly immunonegative (*) medulloblastoma #13 (K), revealing cytoplasmic and nuclear staining (L).