CA1 and breast cancer: To this end, it has been reported that CA I is involved in the aetiology and progression of atherosclerosis,36 as well as vision loss,38 and that CA I is also implicated in the microcalcification and tumorigenesis in breast cancer.32 Given the general lack of evidence that CA I is present in human plasma in previous studies, our findings imply that this Zn metalloprotein is rapidly cleared from the bloodstream by yet unknown biochemical processes.