Is a parameter of a biological state or condition that can be useful to evaluate the health status of a person, select the appropriate intervention or monitor the effect of a treatment. Examples of biomarkers used for health monitoring are platelets, neutrophils and lymphocytes. Examples of biomarkers used for cancer diagnosis or during follow-ups are: CA-125 (ovarian cancer), CEA (colorectal cancer), PSA (prostate cancer), BRCA1/BRCA2 (breast and ovarian cancer), HER2 (breast cancer), etc
