Expression of Oct4 Protein in Astrocytic Tumours: Histopathologic and Immunohistochemical Study EC18-EC21
Engy Samir Mohamed Abdel-Moneim Al-Hariry,
16 Fatma Roshdy St-Al-Haram-Giza-Floor 5, Apartment 603, Cairo, Egypt.
Introduction: The majority of gliomas in adults are resistant to therapy. Therapy resistance has been attributed to the presence of Cancer Stem Cells (CSCs). Oct4 is a transcription factor required for maintaining the pluripotency and self-renewal of CSCs. It was found to be highly expressed in astrocytomas and other tumours.
Aim: Assessment of immunohistochemical expression of Oct4 protein, being a target antigen for cancer immunotherapy of astrocytic tumours, and the correlation between Oct4 expression and the grades of astrocytoma.
Materials and Methods: In this retrospective cross-sectional study, 66 paraffin-embedded biopsies of astrocytomas were collected including; 12 cases of Grade I, 19 cases of Grade II, 15 cases of Grade III and 20 cases of Grade IV. All the cases were studied immunohistochemically using anti-Oct4 protein antibody. Chi-square test or Fisher’s-exact test was used to examine the relationship between qualitative variables. All tests were two-tailed. The p-value <0.05 was considered significant.
Results: Oct4 was expressed in 30 cases. The higher the grade of astrocytoma, the more was the expression (p-value=0.006) and the percentage of positive tumour cells (p-value=0.039). The expression was both nuclear and cytoplasmic. The intensity of expression was variable within the same tumour. Oct4 was not expressed in normal brain tissue.
Conclusion: Oct4 is a stem cell marker that is involved in the development of CSCs, and accordingly, the development of many tumours including astrocytomas.