Different subcellular localization of ALCAM molecules in neuroblastoma: Association with relapse.
BACKGROUND
The Activated Leukocyte Cell Adhesion Molecule (ALCAM/CD166), involved in nervous system development, has been linked to tumor progression and metastasis in several tumors. No information is available on ALCAM expression in neuroblastoma, a childhood neoplasia originating from the sympathetic nervous system.


METHODS
ALCAM expression was analysed by immunofluorescence and immunohistochemistry on differentiated neuroblastoma cell lines and on archival specimens of stroma-poor, not MYCN amplified, resectable neuroblastoma tumors, respectively.


RESULTS
ALCAM is variously expressed in neuroblastoma cell lines, is shed by metalloproteases and is cleaved by ADAM17/TACE in vitro. ALCAM is expressed in neuroblastoma primary tumors with diverse patterns of subcellular localization and is highly expressed in the neuropil area in a subgroup of cases. Tumor specimens showing high expression of ALCAM at the membrane of the neuroblast body or low levels in the neuropil area are associated with relapse (P=0.044 and P<0.0001, respectively). In vitro differentiated neuroblastoma cells show strong ALCAM expression on neurites, suggesting that ALCAM expression in the neuropil is related to a differentiated phenotype.


CONCLUSIONS
Assessment of ALCAM localization by immunohistochemistry may help to identify patients who, in the absence of negative prognostic factors, are at risk of relapse and require a more careful follow-up.
Corrias
Maria Valeria
MV
Laboratory of Oncology, Gaslini Institute, Genoa, Italy.
Gambini
Claudio
C
Gregorio
Andrea
A
Croce
Michela
M
Barisione
Gaia
G
Cossu
Claudia
C
Rossello
Armando
A
Ferrini
Silvano
S
Fabbi
Marina
M
D020410:Activated-Leukocyte Cell Adhesion Molecule / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D009364:Neoplasm Recurrence, Local; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology*; D019581:Neuropil / Q000378:metabolism; D021381:Protein Transport; D012008:Recurrence
D020410:Activated-Leukocyte Cell Adhesion Molecule