Assessment of GLUT 1 expression in different grades of oral epithelial dysplasia and squamous cell carcinoma - An immunohistochemical study.

Abstract

Background: Increased glucose uptake primarily mediated by Glucose Linked Transporter type 1 (GLUT1) is identified as one of the vital predictors of malignancies.

Aim and objective: To compare and correlate GLUT1 expression in normal oral mucosa, different grades of oral epithelial dysplasia (OED) and oral squamous cell carcinomas (OSCCs).

Materials and methods: The present retrospective study was conducted during the period of September 2023-August 2024 on a total of 45 (n = 45) histologically graded formalin fixed paraffin embedded sections of OEDs, OSCC and normal oral mucosa that were immunostained with GLUT1. The samples were randomly divided into Study groups: Group 1 (OEDs), Group 2 (OSCC) and Control group (normal oral mucosa). Balanced equivalence sampling method was applied across all the groups with 15 samples each (n = 15). Group 1 and Group 2 were further subdivided into subgroups as subgroup 1.1 (mild dysplasia), subgroup 1.2 (moderate dysplasia), subgroup 1.3 (severe dysplasia), subgroup 2.1 (well differentiated SCC), subgroup 2.1 (moderately differentiated SCC), and subgroup 2.3 (poorly differentiated SCC) with five samples each (n = 5). Samples with membrane staining were classified as having a positive GLUT1 expression. Remmele and Stegner's immunoreactive score (IRS) was used to rate the staining intensity and percentage of positive cells. A bright field microscope was used to examine the slides, and photomicrographs were obtained to determine the proportion of positive cells. For semi-quantitative analysis, three regions (per case) with the highest GLUT1 expression were chosen at random. The mean value of the percentages was computed after the percentage of GLUT1 expression was measured. SPSS Version 19.0 was used for data analysis. Mean, frequencies, and percentages were used for categorical variables. The statistical analyses were done using Mann-Whitney and Kruskal Wallis Tests. A P value < 0.05 was considered statistically significant for all tests.

Results: Group 1 had a total mean IRS score of 7.93 ± 2.219 with subgroup 1.1 (5.20 ± 1.095), subgroup 1.2 (9.00 ± 0.000) and subgroup 1.3 (9.60 ± 1.342), respectively, with highly significant P value (P < 0.001). Group 2 had a total mean IRS score of 9.40 ± 2.230 with subgroup 2.1 (7.20 ± 1.643), subgroup 2.2 (9.00 ± 0.000) and subgroup 2.3 (12.00 ± 0.000) with highly significant P value (P < 0.001). However, the control group reported the least total mean IRS score of 2.47 ± 1.407 (P > 0.05). However, there was no significant difference in the Mean IRS between Group 1 (epithelial dysplasia) and Group 2 (OSCC) (P = 0.150). When the mean IRS differences between Group 1 (epithelial dysplasia) and normal control, as well as between Group 2 (OSCC) and normal control, were compared, the results were determined to be highly significant (P = 0.000).

Conclusion: Increased expression of GLUT 1 protein in OEDs and OSCC can be a prognostic indicator of malignant changes and treatment outcomes.