Transforming growth factor beta s (
TGF beta s) are multifunctional
growth factors which show differential expression both temporally and spatially and exert pleiotropic effects during
carcinogenesis. Although all three mammalian
isoforms of
TGF beta share considerable sequence similarity, they appear to have distinct functions in health and disease, such as embryogenesis, wound healing and tumourigenesis. Much of our knowledge about the relationship between
TGF beta s and
breast cancer is based on publications on
TGF beta 1 but the role of
TGF beta 3 in the progression of
breast cancer has not been well documented. In the present study, the expression of
TGF beta 1 and
TGF beta 3 was assessed by immunohistochemistry. Of the 153 invasive
breast cancer tissues,
TGF beta 1 was expressed strongly in 25 and moderately in 98 cases. The immunoreactivity of
TGF beta 3 was comparable with
TGF beta 1, which was expressed strongly in 21 and moderately in 104 cases. The two
isoforms were coexpressed in 111 (72.5%) tumours and were absent in 16 cases (10%). Immunostaining for
TGFb3 but not
TGF beta 1 was inversely correlated with overall survival (p = 0.0204). When combined with lymph node involvement,
TGFb3 became an even more significant prognostic factor for overall survival (p = 0.0003), i.e. patients with node
metastasis and positive
TGFb3 expression had a worse prognosis: the risk of death for these patients was thirteen-fold greater than those who had no node involvement. The fact that it has been reported previously that high
TGF beta 3 plasma levels in patients with untreated early stage
breast cancer were correlated with subsequent
lymph node metastasis and it was observed in the present study too, that
TGF beta 3 expression in breast tumours was an independent predictor of overall survival, led us to suggest that the simultaneous measurement of
TGF beta 3 in plasma and its expression in resected tumour tissues in the same cohort of patients may prove to be an important parameter in assessing tumour progression.