Measuring serum human epididymis secretory protein autoantibody as an early biomarker of lung cancer

Human epididymis protein 4, a novel potential biomarker for diagnostic and prognosis monitoring of lung cancer

OBJECTIVE

This study aimed to explore the application value of human epididymis protein 4 (HE4) in diagnosing and monitoring the prognosis of lung cancer.

METHODS

First, TCGA (The Cancer Genome Atlas) databases were used to analyze whey-acidic-protein 4-disulfide bond core domain 2 (WFDC2) gene expression levels in lung cancer tissues. Then, a total of 160 individuals were enrolled, categorized into three groups: the lung cancer group (n = 80), the benign lesions group (n = 40), and the healthy controls group (n = 40). Serum HE4 levels and other biomarkers were quantified using an electro-chemiluminescent immunoassay. Additionally, the expression of HE4 in tissues was analyzed through immunohistochemistry (IHC). In vitro cultures of human airway epithelial (human bronchial epithelial [HBE]) cells and various lung cancer cell lines (SPC/PC9/A594/H520) were utilized to detect HE4 levels via western blot (WB).

RESULTS

Analysis of the TCGA and UALCAN (The University of Alabama at Birmingham Cancer Data Analysis Portal) databases showed that WFDC2 gene expression levels were upregulated in lung cancer tissues (p < 0.01). Compared with the control group and the benign group, HE4 was significantly higher in the serum of patients with lung cancer (p < 0.001). Receiver operating characteristic (ROC) analysis confirmed that HE4 had better diagnostic efficacy than classical markers in the differential diagnosis of lung cancer and benign lesions and had the highest diagnostic value in lung adenocarcinoma (area under the ROC curve [AUC] = 0.826). HE4 increased in early lung cancer and positively correlated with poor prognosis (p < 0.001). Moreover, the results of WB and IHC revealed that the expression of HE4 was increased in lung cancer cells (SPC/A549/H520) and lung cancer tissues but decreased in PC9 cells with a lack of exon EGFR19 (p < 0.05).

CONCLUSION

Serum HE4 emerges as a promising novel biomarker for the diagnosis and prognosis assessment of lung cancer.

Identification of biomarkers for the early detection of non-small cell lung cancer: a systematic review and meta-analysis

Lung cancer (LC) causes few symptoms in the earliest stages, leading to one of the highest mortality rates among cancers. Low-dose computerised tomography (LDCT) is used to screen high-risk individuals, reducing the mortality rate by 20%. However, LDCT results in a high number of false positives and is associated with unnecessary follow-up and cost. Biomarkers with high sensitivities and specificities could assist in the early detection of LC, especially in patients with high-risk features. Carcinoembryonic antigen (CEA), cytokeratin 19 fragments and cancer antigen 125 have been found to be highly expressed during the later stages of LC but have low sensitivity in the earliest stages. We determined the best biomarkers for the early diagnosis of LC, using a systematic review of eight databases. We identified 98 articles that focussed on the identification and assessment of diagnostic biomarkers and achieved a pooled area under curve of 0.85 (95% CI 0.82-0.088), indicating that the diagnostic performance of these biomarkers when combined was excellent. Of the studies, 30 focussed on single/antigen panels, 22 on autoantibodies, 31 on miRNA and RNA panels, and 15 suggested the use of circulating DNA combined with CEA or neuron-specific enolase (NSE) for early LC detection. Verification of blood biomarkers with high sensitivities (Ciz1, exoGCC2, ITGA2B), high specificities (CYFR21-1, antiHE4, OPNV) or both (HSP90α, CEA) along with miR-15b and miR-27b/miR-21 from sputum may improve early LC detection. Further assessment is needed using appropriate sample sizes, control groups that include patients with non-malignant conditions, and standardised cut-off levels for each biomarker.

Detection of serum HE4 levels contributes to the diagnosis of lung cancer

Lung cancer (LC) is the most frequently diagnosed cancer and is the leading cause of cancer-associated death. Serum markers that exhibit high sensitivity and specificity for LC may assist in the diagnosis and prognosis of LC. The banked serum samples from 599 individuals, including 201 healthy controls, 124 patients with benign lung diseases, and 274 LC cases, were used. The serum concentrations of biomarkers were determined by electrochemiluminescence immunoassay and chemiluminescence immunoassay. The results showed that the serum human epididymis secretory protein 4 (HE4) levels in the LC group were significantly higher than in the healthy and benign lung disease groups. The serum levels of HE4, NSE, and CYFRA21-1 were significantly higher in patients with LC compared to those in the benign lung disease group. The area under the area under the curve (AUC) of HE4 for discriminating LC from healthy controls was 0.851 (95% CI, 0.818-0.884) and 0.739 (95% CI, 0.695-0.783), 0.747 (95% CI, 0.704-0.790), 0.626 (95% CI, 0.577-0.676), and 0.700 (95% CI, 0.653-0.747) for NSE, CYFRA21-1, SCC, and ProGRP, respectively. The AUC value of the combination of serum HE4 combined with NSE, CYFRA21-1, SCC, and proGRP for cancer diagnosis was 0.896 (95% CI, 0.868-0.923). In early LC, the AUC value of HE4 for discriminating early LC from healthy controls was 0.802 (95% CI, 0.758-0.845), 0.728 (95% CI, 0.679-0.778), 0.699 (95% CI, 0.646-0.752), 0.605 (95% CI, 0.548-0.662), and 0.685 (95% CI, 0.630-0.739) for NSE, CYFRA21-1, SCC, and ProGRP, respectively. The AUC value of the combination of serum HE4 with NSE, CYFRA21-1, SCC, and proGRP for early LC was 0.867 (95% CI, 0.831-0.903). Serum HE4 is a promising LC biomarker, particularly for early-stage LC. Measuring serum HE4 levels may improve the diagnostic efficiency of LC.

Blood protein biomarkers in lung cancer

Lung cancer has consistently ranked first as the cause of cancer-associated mortality. The 5-year survival rate has risen slowly, and the main obstacle to improving the prognosis of patients has been that lung cancer is usually diagnosed at an advanced or incurable stage. Thus, early detection and timely intervention are the most effective ways to reduce lung cancer mortality. Tumor-specific molecules and cellular elements are abundant in circulation, providing real-time information in a noninvasive and cost-effective manner during lung cancer development. These circulating biomarkers are emerging as promising tools for early detection of lung cancer and can be used to supplement computed tomography screening, as well as for prognosis prediction and treatment response monitoring. Serum and plasma are the main sources of circulating biomarkers, and protein biomarkers have been most extensively studied. In this review, we summarize the research progress on three most common types of blood protein biomarkers (tumor-associated antigens, autoantibodies, and exosomal proteins) in lung cancer. This review will potentially guide researchers toward a more comprehensive understanding of candidate lung cancer protein biomarkers in the blood to facilitate their translation to the clinic.

Anti-Cancer Auto-Antibodies: Roles, Applications and Open Issues

Auto-antibodies are classically associated with autoimmune diseases, where they are an integral part of diagnostic panels. However, recent evidence is accumulating on the presence of auto-antibodies against single or selected panels of auto-antigens in many types of cancer. Auto-antibodies might initially represent an epiphenomenon derived from the inflammatory environment induced by the tumor. However, their effect on tumor evolution can be crucial, as is discussed in this paper. It has been demonstrated that some of these auto-antibodies can be used for early detection and cancer staging, as well as for monitoring of cancer regression during treatment and follow up. Interestingly, certain auto-antibodies were found to promote cancer progression and metastasis, while others contribute to the body's defense against it. Moreover, auto-antibodies are of a polyclonal nature, which means that often several antibodies are involved in the response to a single tumor antigen. Dissection of these antibody specificities is now possible, allowing their identification at the genetic, structural, and epitope levels. In this review, we report the evidence available on the presence of auto-antibodies in the main cancer types and discuss some of the open issues that still need to be addressed by the research community.