Grant: Travel Awards - Institute Community Support

Breast cancer is the leading cause of cancer associated death in Canadian women. Clinically validated biomarkers provide useful information on the mechanism of the disease. We have discovered a novel biomarker named Bik for breast cancer that provides critical information on outcomes of breast cancer patients. Bik is a protein that normally induces programmed cell death; the immune system then disposes of damaged and potentially dangerous cells. Interestingly however, we found that high amounts of Bik in patient tumors were associated with poor survival outcomes. This observation points at a novel tumor-promoting role of Bik in tumor tissue. Indeed, we found that ectopic expression of Bik in breast cancer cells induced sub-lethal levels of apoptosis. During the late stages of apoptosis, nuclear DNA is fragmented for eventual disposal. Interestingly, we found that in Bik expressing cells, nuclear DNA is only partially fragmented and cells survive with this DNA damage. Damaged DNA in the cells is repaired by DNA repair machinery which inadvertently introduces mutations during the DNA repair process. Mutations in critical genes causes cellular transformation and contribute to cancer aggression. Interestingly, we found that Bik expressing breast cancer cells adopted a more aggressive phenotype. Thus, we have identified a potential mechanism by which Bik contributes to tumor aggression.