Aims: To elucidate the clinicopathological significance of Y416Src and Y527Src expression in breast cancer, and to evaluate their usefulness as potential predictive markers for Src inhibitors.
Background: c-Src is a non-receptor tyrosine kinase; the active form of c-Src can catalyse tyrosine phosphorylation. The expression and activity of c-Src correlates with cell adhesion, survival, angiogenesis, migration, invasion and osteoclast function. There are limited clinicopathological data on Src expression and breast cancer characteristics.
Methods: An immunohistochemical study was performed to determine the expression of c-Src, Y416Src, and Y527Src in 215 consecutive breast cancer cases. The correlation of their expression with various clinicopathological factors was analysed statistically.
Results: c-Src was expressed in all 215 cases (100%). Y416Src was expressed in 174 cases (80.9%) and was highly expressed in 30 cases (14.0%). Y527Src was expressed in 138 cases (64.2%) and was highly expressed in 11 cases (5.1%). High expression of Y416Src was significantly associated with metastatic disease (p=0.0327), whereas high expression of Y527Src was significantly associated with metastatic disease (p=0.0004), clinical stage (p=0.0062), as well as HER2 status (p=0.0149). High expression of either Y416Src or Y527Src was significantly correlated with poor overall survival (p=0.0049 and p<0.0001, respectively). In the 192 curatively operated cases, Y416Src expression was significantly associated with poor disease-free survival (p=0.0088).
Conclusion: Although further studies to assess Src activity are necessary, investigation of Src inhibitors for breast cancer including in-vivo models should be encouraged more.