Doublecortin immunolabeling in canine gliomas with distinct degrees of tumor infiltration

Abstract

Increased doublecortin (DCX) immunolabeling at the tumor margins has been associated with tumor infiltration in human glioma and canine anaplastic meningioma. No association between DCX immunolabeling and glioma infiltration has been reported in dogs, to our knowledge. Here we compare the DCX immunolabeling in 14 diffusely infiltrating gliomas (gliomatosis cerebri) and 14 nodular gliomas with distinct degrees of tumor infiltration. Cytoplasmic DCX immunolabeling was classified according to intensity (weak, moderate, strong), distribution (1 = <30% immunolabeling, 2 = 30–70% immunolabeling, 3 = >70% immunolabeling), and location within the neoplasm (random or at tumor margins). Immunolabeling was detected in 6 of 14 (43%) diffusely infiltrating gliomas and 8 of 14 (57%) nodular gliomas. Diffusely infiltrating gliomas had moderate and random immunolabeling, with distribution scores of 1 (4 cases) or 2 (2 cases). Nodular gliomas had strong (6 cases) or moderate (2 cases) immunolabeling, with distribution scores of 1 (3 cases), 2 (3 cases), and 3 (2 cases), and random (6 cases) and/or marginal (3 cases) immunolabeling. Increased DCX immunolabeling within neoplastic cells palisading around necrosis occurred in 4 nodular gliomas. DCX immunolabeling was not increased at the margins of diffusely infiltrating gliomas, indicating that DCX should not be used as an immunomarker for glioma infiltration in dogs.

Diagnostic immunohistochemistry of primary and secondary central nervous system neoplasms of dogs and cats

“…15,23,55 In addition, strong cytoplasmic DCX immunolabeling at the tumor margins is associated with tumor infiltration in human glioma, but no evidence has yet supported that association in canine and feline gliomas. 14,55…”

“…15,79 DCX, a microtubule-associated protein that regulates neuroblast migration during embryonal life, can be utilized to detect neuronal progenitor cells (neuronal differentiation) in canine and feline gliomas. 15,23,55 In addition, strong cytoplasmic DCX immunolabeling at the tumor margins is associated with tumor infiltration in human glioma, but no evidence has yet supported that association in canine and feline gliomas. 14,55 Nuclear immunolabeling for NeuN and cytoplasmic immunolabeling for β-3 tubulin (both immunomarkers for mature neurons) occurs most often in high-grade canine oligodendrogliomas compared to low-grade oligodendrogliomas, 27,81 but the clinical significance of these findings remains elusive.…”

“…15,23,55 In addition, strong cytoplasmic DCX immunolabeling at the tumor margins is associated with tumor infiltration in human glioma, but no evidence has yet supported that association in canine and feline gliomas. 14,55 Nuclear immunolabeling for NeuN and cytoplasmic immunolabeling for β-3 tubulin (both immunomarkers for mature neurons) occurs most often in high-grade canine oligodendrogliomas compared to low-grade oligodendrogliomas, 27,81 but the clinical significance of these findings remains elusive. Feline gliomas lack NeuN immunolabeling.…”

“…DCX, a microtubule-associated protein that regulates neuroblast migration during embryonal life, can be utilized to detect neuronal progenitor cells (neuronal differentiation) in canine and feline gliomas. 15,23,55 In addition, strong cytoplasmic DCX immunolabeling at the tumor margins is associated with tumor infiltration in human glioma, but no evidence has yet supported that association in canine and feline gliomas. 14,55…”