FasL is more frequently expressed in liver metastases of colorectal cancer than in matched primary carcinomas.

摘要: Colorectal carcinoma cells have recently been shown to express Fas ligand (FasL). This could allow the tumour evade activated tumour-infiltrating lymphocytes (TILs) by inducing their apoptosis and would thus promote survival possibly metastasis formation. To test this hypothesis in vivo we analysed expression of FasL mRNA protein paired tissue samples normal colonic mucosa (N), primary colorectal carcinomas (T) metastases (M) from a total 21 patients four different methods. Additionally, presence activation status infiltrating lymphocytes, which might contribute amount tissue, was determined semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) same samples. The frequency detection 30-40% T 60-100% M, depending on sensitivity method. Simultaneously, CD25 mRNA, used as measure number TILs, 90% lower M than T. increased liver therefore not due TILs. We conclude that metastasizing subpopulations more frequently may be able eliminate TILs via Fas/FasL-induced or other hitherto unknown mechanisms.