Mast Cells in Mammary Carcinogenesis: Host or Tumor Supporters?

BACKGROUND/AIM The effects of mast cells on carcinogenesis is not yet fully understood. This work aimed to disclose the role of mast cells in mammary carcinogenesis in a rat model. MATERIALS AND METHODS Mammary tumors were induced by the administration of N-methyl-N-nitrosourea (MNU) in three groups of rats. Animals from one group were treated with ketotifen immediately after MNU administration, and animals from another only received ketotifen after the development of the first mammary tumor. The biochemical profile was determined. Mammary tumors were evaluated by histopathology and immunohistochemistry. RESULTS Animals from ketotifen-treated groups developed fewer mammary tumors, higher number of mammary lesions and had lower histamine levels when compared to non-treated animals. Animals treated with ketotifen immediately after MNU exhibited the lowest proliferative and apoptotic indexes. CONCLUSION The mainly positive effect of the inhibition of mast cell degranulation seems to be the reduction of tumor proliferation when the mast cell degranulation was inhibited before tumor development.