Breast Cancer Vaccines
BioLife Science is developing two types of tumor vaccines both directed to the cell surface receptor HER-2 which is overexpressed in a significant proportion of breast cancers (see Background). We have chosen this target for two reasons. First, overexpression of HER-2 is correlated with bad prognosis and resistance to conventional therapy, thus there is a demand for new treatment concepts. Second, the successful results in the usage of the anti-HER-2 antibody Trastuzumab prove the effectiveness of anti-HER-2 antibodies. A vaccine inducing the continuous generation of anti-HER-2 antibodies by the patient's own immune system should further increase the efficacy of this treatment strategy.
How tumor vaccines work
Growth factors (red) stimulate the proliferation of cells by binding to a
receptor on the cell surface (grey). Tumor cells frequently express too many
or mutant receptors, which leads to a continuous cell proliferation and
tumor growth.
A tumor vaccine induces the generation of receptor-specific antibodies (blue)
by the patient's immune system. These antibodies bind to the receptors and block
the growth signal (1). In addition, cell bound antibodies attract cytotoxic cells
and phagocytes which kill the tumor cell (antibody-dependent cytotoxicity and phagocytosis, 2).
Additionally, tumor vaccines may also stimulate a cellular immune response (killing of tumor cells by antigen-specific cytotoxic T lymphocytes).
When tumor vaccines can be used
There are different situation where tumor vaccines could be used:
Treatment of cancer patients: either as a substitution for or an addition to adjuvant, chemo- and/or endocrine therapy in patients with clearly characterized tumors.
Active vaccination against the emergence of malignant disorders in healthy persons with various risk profiles (hereditary or genetic disposition for certain cancer types).
Next: HerVac®