This study aimed to determine the expression of the Cap43 gene in supraglottic laryngeal squamous cell carcinoma, and to evaluate any correlation between Cap43 gene expression and tumour-associated macrophage infiltration.

Four human head and neck squamous cell carcinoma cell lines were cultured (Hep2, KB, Ca9-22 and HSC-3) and expression of the Cap43 gene was analysed by Western blotting. In addition, paraffin-embedded samples of supraglottic laryngeal squamous cell carcinoma and normal supraglottic laryngeal mucosa from 84 patients were analysed immunohistochemically using antibodies to Cap43 and cluster of differentiation 68 glycoprotein. Patients' clinical status was compared with their immunohistochemical results.

All four head and neck squamous cell carcinoma cell lines exhibited Cap43 expression. The Hep2, Ca9-22 and HSC-3 cells showed a markedly higher level of Cap43 protein than the KB cells. A statistically significant difference was found in Cap43 expression, comparing different differentiation levels and comparing different metastasis stages, for supraglottic squamous cell carcinoma. The number of tumour-associated macrophages correlated with expression of Cap43, not only in the tumour area (r = 0.3708, p = 0.0005) but also in the peritumour area (r = 0.2847, p = 0.0087).

In supraglottic laryngeal squamous cell carcinoma, overexpression of the Cap43 gene is associated with tumour differentiation and acts an important suppressive factor in the process of tumour metastasis. The Cap43 gene may be a cancer-specific marker. High expression of the Cap43 gene appeared to correlate with infiltration of tumour-associated macrophages.