Background
Transglutaminase 2 (TGM2) is a protein expressed in several isoforms in both intra- and extra-cellular tissue compartments. It has multiple functions that are important in cancer biology and several small studies have suggested expression of TGM2 in breast cancers is associated with a poorer prognosis. The
Conclusion
Tissue compartment and hormone receptor status differences in the effect of TGM2 expression on clinical outcomes of breast cancer may reflect the different functions of TGM2.
Methods
We carried out TGM2 immunostaining of tissue micro-arrays comprising 2169 tumour cores and scored these for both intra- and extra-cellular and expression.
Results
Intra-cellular (tumour cell) TGM2 positivity was associated with a better prognosis (HR = 0.74, 95% CI 0.59-0.92) with a larger effect stronger in hormone-receptor-negative cases (HR = 0.56, 95% CI 0.37-0.85). Extra-cellular (stromal) TGM2 expression was associated with a poorer prognosis (HR = 1.47, 95% CI 1.06-2.03) with a stronger association in hormone-receptor-positive cases (HR = 1.60, 95% CI 1.09-2.34).