Breast cancers develop initially as “solid” tumours and are classified according to the cells in the normal breast that they resemble most closely. Some appear abruptly, but most are slow-growing; a result of a series of many steps in which mutations accumulate in normal breast cells to form cancer. Early stage breast cancer indicates a tumour that has not yet crossed the basement membrane barrier that surrounds the mammary gland. Advanced breast cancers have crossed the basement membrane into surrounding tissues, where they may invade and establish new tumours (metastasize) in the bone, liver, brain and other organs. If confined to the breast, most breast cancers can be cured or treated through surgery, radio- chemo- and/ or hormone therapies.
Currently there are no Health Canada or FDA approved stem cell treatments available for breast cancer. While some forms of cancerous tumours can be treated with a hematopoietic (blood) stem cell transplant, not all tumours can be treated this way and breast cancer is one that, up to now, has been resistant to this type of therapy. Researchers are using stem cells to study the underlying cause of breast cancer (which may originate in the stem cells themselves), to see how they are different from other types of solid tumour cancers and to quickly and safely test drugs that might help curb the spread of the disease.