Immunohistochemical analysis of cancer-associated fibroblasts and podoplanin in head and neck cancer

To immunohistochemically evaluate the association between the presence of cancer-associated fibroblasts (CAFs) and the tumour expression of podoplanin (PDPN) in head and neck squamous cell carcinoma (HNSCC) and their association with clinicopathological variables. A tissue microarray (TMA) with biopsy sections from patients diagnosed with HNSCC was stained with antibodies against the CAFs marker, ?-smooth muscle actin (?-SMA), and PDPN. We subsequently evaluated their expression to determine the association between them and with clinicopathological variables including age, primary tumour site, TNM stage, and tumour differentiation grade. Positive reaction to ?-SMA was observed in the tumour stroma, revealing spindle-shaped cells compatible with CAFs, which showed a high expression in 62% of cases and a significant association with laryngeal carcinomas, advanced clinical stages, and lower tumour differentiation (P ? 0.05). PDPN staining on tumour cells showed low expression in 72% of cases, and it was not associated with any clinicopathological variable or with the presence of CAFs. The presence of CAFs in the tumour stroma is related to an aggressive phenotype and could increase as the disease progresses, although based on our findings, it would have no relationship, at least directly, with the expression of PDPN.