Objectives/hypothesis: The aim of the study was to determine the clinical significance of the expression of Glut1 and Glut3 proteins in biopsy specimens of squamous cell carcinoma (SCC) of the larynx.
Study design: A retrospective study.
Methods: Using immunohistochemistry, we immunostained sections of formalin-fixed, paraffin-embedded tissues from 48 biopsies of invasive SCC of the larynx for Glut1 and Glut3. The percentages of positive cells were recorded, then correlated with overall patient survival using the Kaplan-Meier method and the Breslow-Gehan-Wilcoxon test for statistical significance.
Results: All cases were positive for Glut1, and Glut1 expression was not associated with survival difference at any cut-off value. Eighteen (38%) of the cases were Glut3-negative and 30 (62%) were Glut3-positive. Glut3-positive cases were associated with poorer survival than Glut3-negative cases (P =.0336). No significant difference was found between Glut3-negative and Glut3-positive groups in respect to sex, tumor site (glottic vs. supraglottic), nodal or distant metastasis, or treatment modality. However, there were significantly more poorly differentiated tumors in the Glut3-positive group than in the Glut3-negative group (27% vs. 0%, respectively; P =.0182, Fisher's Exact Test). After poorly differentiated tumors were excluded from the survival analysis, Glut3 immunoreactivity remained a significant marker of poor prognosis (P =.0385).
Conclusion: Immunohistochemical detection of Glut3 in biopsy specimens of SCC of the larynx is a marker of poorer prognosis.