Lymphocyte showing the phenotype of regulatory T-cells infiltrate colon carcinoma

• Authors: GARAJOVÁ Ingrid; FABIAN Pavel; NENUTIL Rudolf; SLABÝ Ondřej; KOCÁKOVÁ Ilona; GRELL Peter; HANZELKOVÁ Zina; SVOBODA Marek; VYZULA Rostislav
• Year of publication: 2007
• Type: Conference abstract
• MU Faculty or unit: Faculty of Medicine
• Description: We have previously shown that colon carcinoma (CC) is infiltrated by FOXP3-positive lymphocytes. Although the transcription factor FOXP3 is claimed to be specific for regulatory T (TREG) cells, the canonical TREG population is known to show the CD4+ CD25+ (FOXP3+) immunophenotype. The aim of the current study was therefore to investigate whether FOXP3+ cells infiltrating CC coexpress indeed CD4 and CD25 molecules. Double-staining experiments were therefore performed on serial sections obtained from formalin-fixed, paraffin-embedded specimens of nine cases of CC. The CC infiltrate included numerous CD4+ as well as CD25+ cells; moreover CD4+ cells harboured both FOXP3+ and FOXP3- lymphocytes; similarly, CD25+ cells included both FOXP3+ and FOXP3- lymphocytes. Nevertheless, all the FOXP3+ cells showed simultaneously CD4-positivity; similarly, all the FOXP3+ cells showed simultaneously CD25-positivity. Thus, the FOXP3+ lymphocytes infiltrating CC are characterized by the coexpression of both CD4 and CD25 molecules, and show therefore an immunophenotype overlapping with that of standard CD4+CD25+FOXP3+ TREG cells. The presence of lymphocytes resembling TREG cells within the microenvironment of CC can explain why the CC tumour mass, despite being also infiltrated by cytolytic anti-tumour CD8+/CD4+ lymphocytes, shows however the well known capability to undergo fatal progression. Acknowledgment: This project is supported by Internal Grant Agency, Ministry of Health, Czech Republic. No.: NR/9076-4.