Calbiotech CA15-3 ELISA

SUMMARY AND EXPLANATION 
Breast cancer is the most common life-threatening malignant lesion in women of developed countries today, with approximately 180,000 new cases diagnosed every year. Roughly half of these newly diagnosed patients are node-negative, however 30% of these cases progress to metastatic disease. There are a number of tumor markers that can help clinicians to identify and diagnose which breast cancer patients will have a more aggressive disease. These markers include estrogen and progesterone receptors, DNA ploidy and percent-S phase profile, epidermal growth factor receptor, HER-2/neu oncogene, p53 tumor suppressor gene, cathepsin D, proliferation markers and CA15-3. CA15-3 is most useful for monitoring patients post-operatively for recurrence, particularly in metastatic disease cases. 96% of patients with local and systemic recurrence have elevated CA15-3, which can be used to predict recurrence earlier than radiological and clinical criteria. A 25% increase in the serum CA15-3 is associated with progression of carcinoma. A 50% decrease in serum CA15-3 is associated with response to treatment. CA15-3 is more sensitive than CEA in early detection of breast cancer recurrence. In combination with CA125, CA15-3 has been shown to be useful in early detection of relapse of ovarian cancer. CA15-3 levels are also increased in colon, lung and hepatic tumors.

PRINCIPLE OF THE TEST 
The CA15-3 ELISA test is an adapted solid phase sequential sandwich ELISA. Samples and biotinylated monoclonal antibody are added to wells coated with streptavidin. CA15-3 in the patient sample binds to biotinylated capture antibody. The biotinylated antibody simultaneously binds to the streptavidin coated plate. After a wash step, anti-CA15-3–HRP enzyme conjugate is added and forms a sandwich around captured CA15-3. Unbound antibodies are washed off. TMB substrate is added resulting in the development of a blue color. The concentration of CA15-3 is directly proportional to the color intensity developed. A standard curve is generated relating color intensity to CA15-3 concentration.

STORAGE AND STABILITY 
1. Store the kit at 2-8°C. 
2. Keep microwells sealed in a dry bag with desicants. 
3. The reagents are stable until expiration of the kit. 
4. Do not expose test reagents to heat, sun or strong light