Immunohistochemical expression of ErbB2 in adamantinomatous craniopharyngiomas: a possible target for immunotherapy.

Aim: To determine the immunohistochemical expression of ErbB2 in adamantinomatous craniopharyngiomas (ACP) and to assess its relationship with nuclear expression of β-catenin in surgically resected human ACP tissue sections and to estimate whether these tumors could be candidates for anti-ErbB2 therapy.
Material and Methods: The ErbB2 and β-catenin immunostaining was performed on paraffin embedded tissue sections of 20 ACP using avidin-biotin-peroxidase complex method. ErbB2 immunoreactivity was interpreted according to the American Society of Clinical Oncology/ College of American Pathologists criterions for breast carcinoma.
Results: Foci of nuclear reactivity for β-catenin was observed in all ACP tissue specimens mainly concentrated in whorl like arrays of the epithelial cells. Two (10%) of the cases were score 3+ for ErbB2 as demonstrated by strong complete membrane staining. However, the localization of 3+ ErbB2 cells was different from those with nuclear β-catenin immunoreactivity.
Conclusion: Our preliminary data demonstrate score 3+ staining for ErbB2 in 10% of ACP and different localization of 3+ ErbB2 cells and cells with nuclear β-catenin immunoreactivity. However, because of the small number of cases, further studies with larger samples should be conducted to verify and validate our preliminary data and to determine the effect of ErbB2 protein in ACP cell growth, survival and differentiation.