Immunoassay for Quantifying Squamous Cell Carcinoma Antigen in Serum

Abstract

BACKGROUND Although the benefits of quantifying serum squamous cell carcinoma antigen (SCCa) have been reported, SCCa reagents were no longer available in the US by the late 1990s. Because SCCa quantification still has demonstrated clinical utility, we developed and validated a microtiter plate–based ELISA for measuring SCCa in serum. METHODS We coated microtiter strips overnight with capture anti-SCCa monoclonal antibody, washed the wells, added blocking buffer, and lyophilized the strips. For detection, we used a biotinylated anti-SCCa detection antibody, streptavidin/horseradish peroxidase conjugate, and tetramethylbenzidine/H2O2 substrate. A novel blocking reagent against human antimouse antibodies (HAMA) was evaluated. A reference interval was established with sera from healthy individuals and was confirmed in smokers. RESULTS The assay was linear to 40 μg/L SCCa (slope, 1.00; y intercept, 0.695; R2, 0.996) with a detection limit of 0.3 μg/L. The intraassay imprecision results [mean (CV)] were 2.5 μg/L (3.4%), 18.0 μg/L (3.0%), and 30.7 μg/L (2.4%); interassay imprecision results were 2.0 μg/L (9.9%), 20.0 μg/L (7.6%), and 36.3 μg/L (3.5%). A correlation analysis against an established automated assay generated a slope of 0.976 and a y intercept of −0.193 μg/L (r2 = 0.916). An upper reference limit of 2.1 μg/L SCCa was established at 95% confidence level, with no difference observed in smokers. No correlation between SCCa concentration and age was observed (r2 = 0.0003). At a blocking reagent concentration of 5 mg/L, HAMA interference was eliminated in 3 samples known to produce falsely increased SCCa results. CONCLUSIONS This SCCa ELISA demonstrates acceptable performance characteristics for quantifying serum SCCa and is effective in eliminating HAMA interference.

Technical and clinical performance of a new assay to detect squamous cell carcinoma antigen levels for the differential diagnosis of cervical, lung, and head and neck cancer

“…The median reference range values were 1.1 ng/mL (95th percentile, 2.3 ng/mL) for the European cohort and 1.1 ng/mL (95th percentile, 2.7 ng/mL) for the Chinese cohort. These were both similar to estimations from previous studies: the Architect found 2.1 ng/mL for the 95th percentile in a population of patients in the United States 20 or slightly higher than other reported values. 13 SCCA levels were far higher in the cervical SCC patient population than the other populations, as has been seen previously.…”

An ultrasensitive squamous cell carcinoma antigen biosensing platform utilizing double-antibody single-channel amplification strategy

“…It is regarded as a sensitive tumor marker in patients with cervical cancer. Until now, several techniques have been developed in its detection, such as common sandwich immunosensor (Wu et al, 2013), enzyme-linked immunosensor assay (Erickson et al, 2010), and chemiluminescence immunoassay . All of these methods employ mesoporous materials to amplify signals with complex processes.…”

An ultrasensitive label-free immunosensor based on CdS sensitized Fe–TiO2 with high visible-light photoelectrochemical activity

“…Therefore, SCCA was selected as our model target to study the behaviors of the CdS sensitized Fe-TiO 2 PEC sensor. In recent years, many strategies have been adopted for the detection of SCCA, including radio-immunoassay (Neunteufel et al, 1990), enzyme-linked immunosorbent assay (Çataltepe et al, 2000;Erickson et al, 2010), chemiluminescence immunoassay (Zhang et al, 2011), electrochemistry immunosensor (Li et al, 2011;Wu et al, 2013), glycoproteomic analysis , electrochemiluminescence immunoassay , and controlled release system based homogeneous immunoassay protocol (Gao et al, 2015a). As far as we know, this is the first report to detect SCCA by label-free PEC method based on CdS enhanced Fe-TiO 2 modified ITO electrode.…”