Clinicopathological significance of galectin-1 expression and percentage of galectin-1-expressing T cells in clear-cell renal cell carcinoma

Introduction: This study investigates the clinical significance of galectin-1 expression in carcinoma tissues, plasma, and lymphocytes of patients with clear-cell renal cell carcinoma (RCC).Methods: Galectin-1 expression was investigated, using immunohistochemistry, in 91 clear-cell RCC tissue sections, five angioleiolipomas tissue sections, and three oncocytomas tissue sections. As controls, normal tissue sections adjacent to each tumour and six benign renal tumour sections were examined. Plasma galectin- 1 levels as measured by ELISA were compared in 39 patients. Proportions of galectin-1 expressing CD4+ and galectin-1 expressing CD8+ T lymphocytes in peripheral blood of these patients were detected by flow cytometry.Results: The positive expression rate of galetin-1 in 91 clear-cell RCC tissues sections by immunohistochemistry was 87 (95.6%), with weak expression rate of 35.2 (32/91), moderate expression rate of 51.6% (47/91), and strong expression rate of 13.2% (12/91); whereas 25% (2/8) of renal benign tumour sections showed weak galectin-1 expression, 91.2% (83/91) of non-tumor tissues adjacent to carcinomas had negative expression of galectin-1, and another six (75%) renal benign tumour sections had negative galectin-1 expression. Plasma galectin-1 levels between patients with clearcell RCC and with benign tumours were not significantly difference (p>0.05). In patients with clear-cell RCC, we found a significantly higher proportion of galectin-1-expressing CD4+ lymphocytes (p<0.05) and galectin-1-expressing CD8+ lymphocytes (p<0.05) than in patients with benign tumours. Moreover, the level of galectin- 1 expression was positively associated with stage and Fuhrman grade of clear-cell RCC.Conclusions: Our results suggest that high level of galectin-1 expression in clear-cell RCC tissues may be a useful marker for clear-cell RCC. Our findings also reveal a new clinical significance of galectin-1 — that high proportions of galectin-1-expressing CD4+ and CD8+ lymphocytes were positively associated with poor clinicopathological features.