doi:10.1038/nindia.2014.137 Published online 20 October 2014
Researchers have identified three serum proteins whose concentrations significantly increase in breast cancer patients after chemotherapy: Fas ligand, granzyme B and cytochrome c1. These proteins could potentially be used as biomarkers to indicate the effectiveness of chemotherapy in breast cancer patients.
These three proteins play vital roles in killing cancer cells during chemotherapy — Fas ligand activates a specific enzyme that triggers the controlled death of immune cells, granzyme B induces the death of pathogenic cells by employing toxic T lymphocytes, and cytochrome c secreted by mitochondria also initiates cell death by activating an enzyme-mediated cellular process. To assess the effectiveness of chemotherapy, the researchers measured changes in the serum concentrations of Fas ligand, granzyme B and cytochrome c in breast cancer patients.
They selected 60 breast cancer patients who were scheduled to undergo chemotherapy after surgery and took blood samples from these patients before chemotherapy and three weeks after administrating the first cycle of chemotherapy. They estimated the protein concentrations of these patients using enzyme-linked immunosorbent assay and compared them with those of 30 healthy females.
The researchers found that the serum concentrations of soluble Fas ligand, granzyme B and cytochrome c significantly increased after the first cycle of chemotherapy in stage II and III breast cancer patients. They detected positive correlations between the serum concentrations of Fas ligand and cytochrome c and between granzyme B and cytochrome c in breast cancer patients after chemotherapy.
The researchers say that the serum concentrations of these marker proteins may help clinicians evaluate the effectiveness of chemotherapy in breast cancer patients.