Edinburgh Napier University

  As transforming growth factor betas (TGFβs) are of potential importance in the natural history of breast cancer, it is desirable to develop assays which allow detection of the isoforms of TGFβ, at the level of mRNA and protein in clinical material. In this study an assay capable of detecting the three human TGFβ mRNA species by in situ hybridization is described. The method was validated using as controls, several tissues known to express one or more isoforms of TGFβ. Subsequently, six breast cancers were examined, all of which expressed the three isoforms of TGFβ mRNA. Although there were slight differences in expression between some tumours for certain of the isoforms, in general TGFβ1 and β2 expression was localized predominantly within tumour cells, whilst TGFβ3 localized mainly to smooth muscle underlying blood vessels and residual duct structures. These observations suggest that tumour epithelial cells are the primary sites of synthesis of the TGFβ isoforms in breast cancers.