An enzyme immunoassay for the quantitative measurement of CYFRA21_1 in serum and plasma.
Cytokeratins are epithelial markers whose expression is not lost during malignant transformation. CYFRA 21_1 is a cytokeratin-19 fragment that is soluble in serum and can be used as circulating tumor marker. Although expressed in all body tissues, its major occurrence is in the lung, particulary in lung cancer tissues. CYFRA 21-1 is a sensitive and specific tumor marker of non-small-cell lung cancer (NSCLC), especially of squamous cell subtype (1,2,3). It also reflects the extent of the disease and has an independent prognostic role along with performance status and disease stage in NSCLC (4,5,6). In addition, detection of serum CYFRA 21-1 allows for identification of high risk patients that may benefit from adjuvant chemotherapy (7), and enables the early detection of progressive disease in recurrent NSCLC (8). Additionally, CYFRA 21-1 has been described as a useful marker for esophageal squamous cell carcinoma (9) and for therapy monitoring of bladder cancer (10). The TM_CYFRA21_1 ELISA uses the two mouse monoclonal antibodies KS19.1 and BM19.21 to determine cytokeratin-19 fragments.
The DRG TM_CYFRA21_1 ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. The microtiter wells are coated with a monoclonal [mouse] antibody directed towards a unique antigenic site of the CYFRA21_1 molecule. An aliquot of patient sample containing endogenous CYFRA21_1 is incubated in the coated well with enzyme conjugate, which is an anti- CYFRA21_1 monoclonal antibody conjugated with horseradish peroxidase. After incubation the unbound conjugate is washed off. The amount of bound peroxidase is proportional to the concentration of CYFRA21_1 in the sample. Having added the substrate solution, the intensity of colour developed is proportional to the concentration of CYFRA21_1 in the patient sample.