CDA and breast cancer: Indeed, if the increase in CDA activity and mRNA levels in the blood samples of BC patients is due to the disease itself, then CDA levels in blood could be followed as a marker during routine blood tests in the general population, in a similar manner to the monitoring of prostate-specific antigen (PSA) for prostate cancer24: an increase in CDA activity or mRNA levels in the blood over time could be used as a warning signal for the prescription of a mammogram.