Alpha-internexin expression in medulloblastomas and atypical teratoid-rhabdoid tumors.
OBJECTIVE
To determine whether medulloblastomas and atypical teratoid/rhabdoid tumors express alpha-internexin, an intermediate filament protein that is expressed in normal neurons undergoing maturation and differentiation.


METHODS
28 medulloblastomas and 5 atypical teratoid/rhabdoid tumors were examined for the immunohistochemical expression of alpha-internexin, as well as the neuronal markers peripherin and synaptophysin, and glial fibrillary acidic protein.


RESULTS
Overall, 21 of 28 medulloblastomas (75%) expressed alpha-internexin. More specifically, alpha-internexin expression was observed in 6 of 10 (60%) classic medulloblastomas, 12 of 14 (86%) desmoplastic medulloblastomas, 2 of 3 (67%) nodular medulloblastomas, and in one medullomyoblastoma. Similarly, 4 of 5 (80%) atypical teratoid/rhabdoid tumors expressed alpha-internexin. The extent of staining for alpha-internexin tended to be less than that of synaptophysin for both medulloblastomas (75% vs 93%) and atypical teratoid/rhabdoid tumors (80% vs 100%). In contrast to alpha-internexin, peripherin was expressed in only 4 medulloblastomas and one atypical teratoid/rhabdoid tumor.


CONCLUSIONS
Alpha-internexin is expressed in the majority of medulloblastomas and atypical teratoid/rhabdoid tumors, indicating that these primitive tumors usually exhibit neuronal differentiation.
Kaya
B
B
Department of Pathology, John A. Burns School of Medicine, The Queen's Medical Center, Honolulu, HI, USA.
Mena
H
H
Miettinen
M
M
Rushing
E J
EJ
D000293:Adolescent; D000328:Adult; D002352:Carrier Proteins / Q000032:analysis*; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D002528:Cerebellar Neoplasms / Q000473:pathology*; D002531:Cerebellum / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D007223:Infant; D007381:Intermediate Filament Proteins / Q000032:analysis; D008297:Male; D008527:Medulloblastoma / Q000473:pathology*; D008562:Membrane Glycoproteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000032:analysis; D009474:Neurons / Q000473:pathology; D064531:Peripherins; D018335:Rhabdoid Tumor / Q000473:pathology*; D016708:Synaptophysin / Q000032:analysis; D013724:Teratoma / Q000473:pathology*
D002352:Carrier Proteins; D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C578994:PRPH protein, human; D064531:Peripherins; D016708:Synaptophysin; C046643:alpha-internexin