Expression of functional E-selectin ligands on the plasma membrane of carcinoma cells correlates with poor prognosis in clear cell renal cell carcinoma

Objectives: Given the relatively high frequency of metastatic recurrence of clear cell renal cell carcinoma (ccRCC), reliable prognostic markers of ccRCC, particularly those associated with metastasis, are needed. Here, in search of those factors, we assessed the contribution of sialyl Lewis x (sLe(x)) and sialyl Lewis a (sLe(a)), as well as functional E-selectin ligand carbohydrates expressed on carcinoma cells, to metastasis and consequent poor prognosis in ccRCC. Materials and methods: Patients who underwent surgical resection (curative nephrectomy) for RCC, and whose post-operative pathological diagnosis was ccRCC (n = 117) were enrolled in this study. Expression of sLe(x)/sLe(a) carbohydrate antigens in ccRCC was evaluated by immunohistochemistry with an anti-sLe(x)/sLe(a) monoclonal antibody HECA-452. To evaluate membrane expression of sLe(x)/sLe(a) carbohydrate antigens quantitatively, we employed a histological scoring system used to evaluate membrane expression of human epidermal growth factor receptor 2 (HER2) in breast cancer. We also conducted an E-selectin center dot IgM chimera in situ binding assay to assess expression of functional E-selectin ligand carbohydrates in ccRCC. We then carried out statistical analysis to determine whether membrane expression of HECA-452-reactive sLe(x)/sLe(a) glycans as well as of E-selectin center dot IgM-binding functional E-selectin ligand carbohydrates correlates with progression-free, overall, or cancer-specific survival. Results: Based on HECA-452 immunochemistry, 106 of 117 ccRCC specimens expressed detectable levels of sLe(x)/sLe(a) glycans, primarily on the plasma membrane, and of those, 31 that showed robust membrane expression were judged as HECA-452-positive. Membrane expression of HECA-452-positive sLe(x)/sLe(a) glycans correlated with shortened progression-free and overall survival. Moreover, in in situ analysis, these HECA-452-positive ccRCC tissues were decorated with E-selectin center dot IgM chimeric proteins, calcium-dependently. Comparable analysis in normal kidney showed both HECA-452 positivity and chimera binding almost exclusively in epithelial cells that constitute proximal tubules. Membrane expression of functional E-selectin ligand carbohydrates, as detected by the E-selectin center dot IgM chimera, correlated more significantly with poor prognosis of patients, namely, shortened progression-free, overall and cancer-specific survival, than did HECA-452 positivity. Conclusions: Expression of E-selectin center dot IgM-binding functional E-selectin ligand carbohydrates can serve as a reliable and potentially superior prognostic biomarker of patients with ccRCC. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study assessed the impact of sLe(x) and sLe(a), as well as E-selectin ligand carbohydrates, on metastasis and prognosis in ccRCC. Membrane expression of HECA-452-positive sLe(x)/sLe(a) glycans correlated with shortened progression-free and overall survival. Expression of functional E-selectin ligand carbohydrates showed a more significant correlation with poor prognosis in ccRCC patients than HECA-452 positivity.