Abundant but inactive-state gp140proto-trk is expressed in neuroblastomas of patients with good prognosis.
Steady-state levels of gp140proto-trk in cell lines and tumor tissues of neuroblastoma were examined by immunoblotting with anti-gp140proto-trk. The level of gp140proto-trk varied but showed good correlations with the stage of the tumor and the age of the patients at the time of diagnosis. Moreover, patients with higher expression of gp140proto-trk clearly had a far better survival rate than those with lower expression, suggesting that suppression of gp140proto-trk strongly correlates with the malignant conversion of the tumor. However, we found that neither autophosphorylation of gp140proto-trk nor tyrosine phosphorylation of cellular proteins was elevated in tumors of the higher expression group. These results suggest that gp140proto-trk does not actively participate in the process of transformation or the suppression of malignant conversion. Rather, the higher level of gp140proto-trk may reflect the greater level of differentiation of tumor cells.
Iwata
H
H
Department of Surgery, Branch Hospital, Nagoya.
Ito
T
T
Mutoh
T
T
Ishiguro
Y
Y
Xiao
H
H
Hamaguchi
M
M
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005910:Glioma / Q000737:chemistry; D006801:Humans; D007223:Infant; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D010766:Phosphorylation; D019000:Phosphotyrosine; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis* / Q000378:metabolism; D020917:Receptor, trkA; D017475:Receptors, Nerve Growth Factor / Q000032:analysis* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D011518:Proto-Oncogene Proteins; D017475:Receptors, Nerve Growth Factor; D019000:Phosphotyrosine; D014443:Tyrosine; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA