The Pathological Evaluation of Autophagy-Related Protein (LC3B) and Its Association with the Infiltration of Immune Cells in Glioma

BACKGROUND: Tumor cell autophagy can influence cellular immunity by participation in the recognition and modification of tumor-related antigens. OBJECTIVES: The objective of this study was to evaluate the immunohistochemical expression of the autophagy-related marker; light chain 3B (LC3B) in tumor cells and the assessment of T lymphocytes by a cluster of differentiation 3 (CD3) in gliomas, and to correlate them with the available clinic-pathological variables in glioma patients. MATERIALS AND METHODS: Immunohistochemical staining for LC3B and CD3 was performed on 60 paraffin-embedded glioma tissue. LC3B immunoreactivity score of 0-6 was designated negative, and those scoring 7-12 were considered positive. The median level of CD3 positive T lymphocytes was calculated for both high and low-grade gliomas. In low-grade gliomas, the CD3 expressing T lymphocytes equal to or more than 2.6, were considered positive while in high-grade gliomas, those equal to or more than 16 were considered positive. RESULTS: LC3B expression in tumor cells was detected in 24/60 (40%) of gliomas. Expression of LC3B was significantly more frequent in high-grade gliomas (23/33, 69.7%) compared to low grade ones (1/27, 5%), (p value= 0.000). LC3B expression was correlated with the patients age (P value= 0.047) & histological variants (P value= 0.000). CD3 positive T lymphocytes were significantly more prominent in high-grade gliomas (25/33 , 41.7%) than low-grade ones (2/27, 3.3%), (P value= 0.001). A significant association was noted between CD3 expression and the patients age (P value= 0.003), sex (P value: 0.035) and histological variants (P value= 0.001). LC3B expression in tumor cells was significantly correlated with CD3 positive T lymphocytes (P value: 0.000). CONCLUSION: Autophagic activity of tumor cells and T lymphocyte infiltrates were reported more in high-grade gliomas compared to low-grade ones, giving high-grade gliomas the chance in autophagy target therapy & immunotherapy.