Tumour infiltrating CD25+ FoxP3+ regulatory T cells (Tregs) relate to tumour grade and stromal inflammation in oral squamous cell carcinoma

J Oral Pathol Med (2011) 40 : 636–642 This research is aimed to quantitate and characterize the subtypes of tumour infiltrating lymphocytes (TILs), in particular the presence of FoxP3+ Tregs in different grades of oral squamous cell carcinoma using monospecific antibody staining of formalin‐fixed, paraffin‐embedded tissue sections. The correlation between tumour grade and the intensity of tumour infiltrating lymphocytes was tried to be tested, to assume a putative linkage between them. Thirty‐four cases of histologically proven primary oral squamous cell carcinoma (OSCC) of different grades of differentiation were assorted to groups 1–3. Three‐micron sections of tissue were cut and captured on electrically charged slides (Vision BioSystem, Mount Waverley, Australia) and stained using monospecific antibody against FoxP3+ Treg phenotype (dilution 1:40, Mouse monoclone No: 236A/E7, Ab 20034, IgG1; Abcam, Cambridge, UK). Automated protocols were employed for staining and scoring of staining intensity using Bond^? system (Vision BioSystem). Significant difference in staining intensities (Tregs) was noted among the histologic grades of tumour, where well‐differentiated OSCC had significantly low expression of FoxP3+ Tregs in comparison with moderately and poorly differentiated tumours. A significant linear correlation was established between tumour grade and the intensity of TILs, where high grade tumours (poor differentiation) were more markedly infiltrated. There was also a significant positive correlation between FoxP3+ Tregs and TILs in cases studied. The correlation of these three variables noted in the study (FoxP3+ Tregs, tumour grade and TILs) and their significance in a meta‐analysis may prove useful in targeting patients with high‐risk neoplasms for more aggressive treatment protocols and management strategies.