A recent multicenter study led by our institution demonstrated that local recurrence of non-small cell lung cancer (NSCLC) was significantly more frequent in patients with diabetes, raising the possibility of different tumor biology in diabetics. Epithelial-to-mesenchymal transition (EMT) plays a key role in local tumor recurrence and metastasis. In the present study, we investigated differences of tumor microenvironment between patients with and without diabetes by examining expression of EMT markers. Seventy-nine NSCLC patients were selected from the cohort of our early multicenter study. These patients were classified into 4 groups: 39 with adenocarcinoma with (n = 19) and without (n = 20) diabetes, and 40 with squamous cell carcinoma with (n = 20) and without (n = 20) diabetes. Immunohistochemical expression of eight EMT markers was analyzed, including transforming growth factor-beta (TGF-β), epidermal growth factor receptor (EGFR), insulin-like growth factor 1 receptor (IGF-1R), vimentin, E-cadherin, N-cadherin, HtrA1, and beta-catenin. Five markers (E-cadherin, HtrA1, TGF-β, IGF-1R and vimentin) demonstrated significantly higher expression in diabetics than in non-diabetics in both histology types. N-cadherin had higher expression in diabetics, though the difference did not reach statistical significance. EGFR showed a higher expression in diabetics in squamous cell carcinoma only. Beta-catenin was the only marker with no difference in expression between diabetics versus non-diabetics. Our findings suggest that diabetes is associated with enhanced EMT in NSCLC, which may contribute to growth and invasiveness of NSCLC.
Keywords: Diabetes; Epithelial-to-mesenchymal transition; Non-small cell lung cancer.