Background: Gliomas are the most common subgroup of CNS tumours in children. Histologic grading is a means of predicting the biological behavior of these tumours and survival is strongly correlated with tumour gradation. The IGF system of ligands and receptors are known to play an important role in both normal and neoplastic growth. Recently, nuclear translocation of the type 1 IGF1R has been demonstrated in tumour tissues. Although the IGF1R expression has been described in CNS paediatric tumours, information about the intracellular localization and correlation with tumour grade is lacking.
Objective and Hypotheses: To characterize the expression and intracellular localization of the IGFI receptor in glial tumours from paediatric patients according to WHO 2007 grading.
Method: Twenty-two patients (12 males/ten females), median aged 7.7 years, (range 0.918.2), with gliomas without previous medical treatment were included. Formalin-fixed 5 μm tumour tissue sections were immunostained for IGF1Rβ. IGF1R expression and intracellular localization were scored as positive or negative, nuclear or cytoplasmic respectively. Contingency tables were analyzed using Pearsons χ2 test to assess relationships between IGF1R and tumour grade (low grades III and high grades IIIIV).
Results: IGF1R staining was positive in 11/17 (65%) low grade tumours and in 4/5 (80%) high grade tumours. Low grade tumours showed cytoplasmic localization of IGF1R in 8/11 cases, while in high grade tumours IGF1R localization was mainly nuclear (3/4) (χ2 test: P<0.05).
Conclusion: Our results would indicate that both expression and intracellular localization of the IGF1R are different in low vs high grade glial paediatric tumours, suggesting a potential role for the IGF system in the biological behavior of these tumours. Further studies are necessary to confirm our results.
18 Sep 2014 - 20 Sep 2014