DESCRIPTION

Trophoblast cell surface antigen 2 (TROP2), also named TACSTD2, is a transmembrane glycoprotein. TROP2 plays a role in transducing intracellular calcium signals. It is expressed in trophoblast cells, cornea and multi-stratified epithelia. TROP2 is overexpressed in most carcinomas and is involved in cancer proliferation, migration, invasion, and metastasis. Congenital mutations of TROP2 cause a rare autosomal recessive disease, which may lead to blindness-the gelatinous drop-like corneal disease.

PRINCIPLE OF THE ASSAY

An anti-tag antibody is pre-coated onto the bottom of wells. After adding antigen or samples, Tagged-Capture antibody and HRP-conjugated detection antibody, a sandwich complex is formed in the solution. TMB acts as a HRP substrate, and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns the solution yellow. The color intensity is proportional to the quantity of bound protein, which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	8	1,119.5	41.6	3.7
2	8	266.4	8.2	3.1
3	8	133.8	7.0	5.2

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	1,104.1	43.6	3.9
2	16	261.4	8.5	3.3
3	16	128.8	7.3	5.7

RECOVERY

The recovery of human TACSTD2/TROP2 spiked to three different levels throughout the range of the assay was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:4	99	94-105
	1:8	116	109-126
Cell culture supernatant	1:16	97	95-100
	1:32	101	97-107
Lysate	1:40	86	80-89
	1:80	96	94-100

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The cell culture supernatant was initially diluted 1:2. The lysate was initially diluted 1:640. )

		Human plasma	Cell culture supernatant	Lysate
1:2	Average% of Expected	100	100	100
	Range (%)	-	-	-
1:4	Average% of Expected	104	105	101
	Range (%)	103-105	104-106	100-103
1:8	Average% of Expected	124	110	101
	Range (%)	119-128	107-113	100-102
1:16	Average% of Expected	104	108	102
	Range (%)	80-127	107-110	101-103

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human TACSTD2/TROP2 One-Step ELISA Kit produced at Sunlong Medical™.