Background: Increased expression of Glut1 and Glut3 has been reported in many human cancers, including nonsmall cell lung carcinoma (NSCLC). The aim of this study was to determine the biologic significance of Glut1 and Glut3 overexpression in Stage I NSCLC.
Methods: Using immunohistochemistry and polyclonal anti-Glut1 and anti-Glut3 antibodies, the authors immunostained sections of formalin fixed, paraffin embedded tissues from 289 Stage I NSCLCs. The Kaplan-Meier survival method, the log rank test, and Fisher's exact test were used for statistical analysis.
Results: Of the 289 cases, 49 (17%) were negative for both Glut1 and Glut3, 239 (83%) were Glut1 positive, 61 (21%) were Glut3 positive, 179 (62%) were positive for Glut1 but negative for Glut3, 1 (0.3%) was positive for Glut3 but negative for Glut1, and 60 (21%) were positive for both Glut1 and Glut3. Only 1 of 50 Glut1 negative tumors (2%) was positive for Glut3, whereas 60 of 239 Glut1 positive tumors (25%) were positive for Glut3 (P < 0.0001). Glut1 or Glut3 were detected more often in poorly differentiated and undifferentiated tumors (P < 0.0001 and P = 0.0008, respectively). Overexpression of Glut1 and/or Glut3 was associated with poorer survival (P = 0.0133), especially in patients with well-differentiated and moderately differentiated tumors (P = 0.0017).
Conclusions: In Stage I NSCLC, Glut3 overexpression likely occurs after Glut1 overexpression. The appearance of Glut1 positive clones is associated with aggressive biologic behavior, which is worsened by the emergence of Glut3 positive clones. Glut1 and Glut3 are significant of poor prognosis indicators in cases of NSCLC.