Involvement of granzyme B and perforin in suppressing nodal metastasis of cancer cells in breast and lung cancers

Aims Granzyme B and perforin, which are contained in cytotoxic granules produced by tumour-infiltrating immune cells, have been reported to be involved in suppression of cancer progression. In this study, the relationship between expression of these molecules and clinical factors in cancer patients was studied Methods Tumour tissue obtained from 23 breast cancer patients and 13 lung cancer patients were examined for expression of granzyme B, perforin and B7-1, using an immunohistochemical technique. The percentage of cells positive for expression of these molecules and the clinical status of each case were compared. Results Both granzyme B and perforin were distributed in the cytoplasm of cancer cells in many cases rather than in tumour-infiltrating lymphocytes. This was observed even in cases of early-stage tumours. In both breast and lung cancer patients, the percentage of cells positive for granzyme B and perforin expression was inversely correlated with the status of regional node metastasis. A competitive RT-PCR analysis confirmed that the expression of mRNA from these molecules extracted from the tumours was consistent with the immunohistochemical results. Conclusions Granzyme B and perforin may play a role in the suppression of nodal metastasis of cancer cells in breast and lung cancers.