Immunohistochemical Expression of TGF-Β1, SMAD4, SMAD7, TGFβRII and CD68-Positive TAM Densities in Papillary Thyroid Cancer

BACKGROUND Papillary thyroid carcinoma (PTC) accounts for 80% of the thyroid malignancies that are characterised by slow growth and an excellent prognosis. Over-expression of SMAD4 protein restores TGF-β signalling, determines a strong increase in anti-proliferative effect and reduces invasive potential of tumour cells expressing it. AIM The study aimed to analyse the immunohistochemical expression of TGF-β1 and its downstream phosphorylated SMAD4, element and of the inhibitory SMAD7 PTC variants and their association with the localisation of TAMs within the tumour microenvironment. METHODS For this retrospective study we investigated 69 patients immunohistochemistry with antibodies against TGF-β, TGF - β-RII, SMAD4, SMAD7, CD68+ macrophages. RESULTS Patients with low infiltration with CD68+ cells in tumour stroma has significantly shorter survival (median of 129.267 months) compared to those with high CD68+ cells infiltration (p = 0.034). From the analysis of CD68+ cells in tumour border and tumour stroma correlated with expression of TGF-β1 / SMAD proteins, we observed that the positive expression of TGF-β1 in tumour cytoplasm, significantly correlated with increased number of CD68+ cells in tumour border (X2 = 5,945; p = 0.015). CONCLUSION TGF-β enhances motility and stimulates recruitment of monocytes, macrophages and other immune cells while directly inhibiting their anti-tumour effector functions.