New insights into the diagnostic characteristics and clinical application of serum biomarkers for lung cancer, and human epididymis protein 4 as a new biomarker?

The value of serum tumor biomarkers used for lung cancer diagnosis is still controversial in clinical practice. This study aimed to further dissect and evaluate the clinical value of serum progastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCC-Ag), carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA21-1) together with a potential new biomarker, the human epididymis protein 4 (HE4) for lung cancer diagnosis, in a large cohort of a Chinese population. Ostensibly healthy individuals, as well as those with benign non-cancerous diseases, benign tumors, lung cancers, and other types of malignancies, were enrolled in the study. Serum ProGRP, NSE, SCC-Ag, CEA, CYFRA21-1, and HE4 were analyzed using the chemiluminescence immunoassay. Data were analyzed utilizing the SPSS and GraphPad Prism software. Detailed dissection of the diagnostic characteristics of serum 6 biomarkers on lung cancer was performed. All 6 biomarkers showed capabilities in characterizing lung cancer from other diseases. ProGRP and NSE were highly specific to small cell lung cancer (SCLC); SCC-Ag was a fair biomarker for NSCLC, specifically SCC histotype; CEA showed specificity to SCLC, followed by NSCLC; CYFRA21-1 was a good biomarker for both SCLC and NSCLC; HE4 showed high specificity to SCLC. For NSCLC characterization, CYFRA21-1+HE4+CEA was the best combinatory pattern in the terms of diagnostic performance (AUC=0.8110). The best combinatory analysis for SCLC was ProGRP+NSE+HE4 (AUC=0.9282). Patients with advanced stage, larger tumor, males, and age 50 or older had higher serum biomarkers levels than those with early stage, smaller tumor, females, and age under 50. Six biomarkers had capabilities in characterizing lung cancer with high or fair diagnostic performance. HE4 is a potential biomarker for both SCLC and NSCLC diagnosis, which merits further investigation.