Evidence for Fas counter attack in vivo from a study of colorectal cancer.

Peritumoural cytotoxic lymphocytic infiltrates in colorectal carcinoma may attack tumour cells by expressing Fas ligand and inducing tumour cell apoptosis. However, tumours may mount a by down regulating their Fas pathway and expressing Fas ligand themselves to induce apoptosis of lymphocytes. This study used immunohistochemistry to demonstrate the presence of CD8+ lymphocytes and Fas ligand. The score of CD8+ peritumoural lymphocytes was negatively correlated with the Fas ligand score of the tumour. The results provide evidence for the Fas theory, but further work would be required to determine if this is a significant factor in the tumour-host interaction.

Matrix metalloproteinases and their inhibitors in gastric cancer.

BACKGROUND: The matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) are strongly implicated in tumour invasion and metastasis. AIMS: To investigate the presence of individual MMPs and TIMPs in gastric cancer. METHODS: The presence of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, and TIMP-2 was identified in a group of gastric cancers (n=74) by immunohistochemistry using monoclonal antibodies. These antibodies were effective on formalin fixed, paraffin wax embedded sections. RESULTS: A large proportion (94%) of gastric cancers contained MMP-2; MMP-1 and MMP-9 were also detected in 73% and 70% of tumours respectively. MMP-3 was only present in 27% of tumours. MMP-1 and MMP-9 were found predominantly in intestinal type tumours. TIMP-1 and TIMP-2 were identified in 41% and 57% of tumours respectively. Immunoreactivity for individual MMPs or TIMPs was not identified in normal stomach. CONCLUSIONS: This study shows the presence of matrix metalloproteinases, particularly MMP-2, and TIMPs in stomach cancer. Antibodies which are effective in formalin fixed, paraffin wax embedded sections are useful for the identification of MMPs and TIMPs in diagnostic specimens.