Thioredoxin Reductase as a Novel and Efficient Plasma Biomarker for the Detection of Non-Small Cell Lung Cancer: a Large-scale, Multicenter study

Abstract

There is an increased demand for efficient biomarkers for the diagnosis of non-small cell lung cancer (NSCLC). This study aimed to evaluate plasma levels of TrxR activity in a large population to confirm its validity and efficacy in NSCLC diagnosis. Blood samples were obtained from 1922 participants (638 cases of NSCLC, 555 cases of benign lung diseases (BLDs) and 729 sex- and age-matched healthy controls). The plasma levels of TrxR activity in patients with NSCLC (15.66 ± 11.44 U/ml) were significantly higher (P < 0.01) than in patients with BLDs (6.27 ± 3.78 U/ml) or healthy controls (2.05 ± 1.86 U/ml). The critical value of plasma TrxR activity levels for diagnosis of NSCLC was set at 10.18 U/ml, with a sensitivity of 71.6% and a specificity of 91.9%. The combination of NSE, CEA, CA19-9, Cyfra21-1, and TrxR was more effective for NSCLC diagnosis (sensitivity and specificity in the training set: 85.6%, 90.2%; validation set: 86.2%, 92.4%) than was each biomarker individually (P < 0.001). TrxR can also efficiently distinguish the metastatic status of the tumor, and it can further differentiate between various histological differentiations. Together, plasma TrxR activity was identified as a convenient, non-invasive, and efficient biomarker for the diagnosis of NSCLCs, particularly for discriminating between metastatic and non-metastatic tumors, or for histologic differentiation.

Plasma activity of Thioredoxin Reductase as a Novel Biomarker in Gastric Cancer

“…Sample collection was performed as described in previous publication 38 . EDTA or anticoagulant-free tubes were used to collect 5 mL samples of preoperative peripheral blood.…”

“…Levels of GC-related tumor markers CEA, CA19-9 and CA72-4 in patients were measured at the indicated time of their visit to the hospital. As described in previous literature 12,38 , CEA, CA19-9 and CA72-4 were analyzed based on electrochemiluminescence immunoassay (ECLIA) using Cobas analyzer (Roche Diagnostics, Mannheim, Germany), and performed according to the manufacturer’s instruction. According to the standard clinical guideline from Chinese society of clinical oncology (CSCO), the cut-off value for the tumor markers were set at 3.5 ng/mL for CEA, 39 U/mL for CA19-9, and 6.9 U/mL for CA72-4 43,44 .…”

“…According to the previous publication 33,36–38 , 5, 5′-dithiobis (2-nitrobenzoic) acid (DTNB) reduction assay was widely applied to measure the TrxR activity in vitro , especially in biological samples. Basically, TrxR activity was measured by the enzymatic activity of TrxR to catalyze the reduction of DTNB with NADPH to 5-thio-2-nitrobenzoic acid (TNB2-), which generates a strong yellow color with maximum absorbance at 412 nm 45–47 .…”

“…In the current study, a specific TrxR inhibitor is used to deduct the background in plasma and determine the reduction of DTNB due only to TrxR activity. TrxR activity was measured by commercially available colorimetric assay kits (Clairvoyance Health Technology, China), and performed according to the manufacturer’s instruction 36–38 . Full details are provided in Supplemental experimental procedures.…”

“…TrxR1, the major isoform of TrxR in the cytoplasm, has been observed to be highly expressed in various malignancies including non-small cell lung carcinoma (NSCLC), breast cancer and hepatocellular carcinoma 33–35 . Previous studies have suggested TrxR as a potential and effective clinical biomarker of early-stage diagnosis and prognosis after chemotherapy in NSCLC, breast cancer, prostate cancer and liver cancer 35–38 . Moreover, TrxR was also reported to be overexpressed in BGC823 GC cell line, and the inhibition of TrxR activity by the TrxR-specific inhibitor resulted in a robust antitumor effect in BGC823 cell line as well as in vivo in GC xenograft mice, suggesting that TrxR may be a potential biomarker involved in the GC diagnosis and evaluation of therapeutic efficiency 39,40 .…”