LncRNAs are important in gene regulation [21]. Many lncRNAs have been shown to be associated with the diagnosis and prognosis of NSCLC [22]. HEIH is a lncRNA [11] originally found in HBV-induced hepatocellular carcinoma, and is highly expressed in NSCLC tissues and cell lines, which can promote the proliferation and metastasis of NSCLC [13]. In this paper highlighted that the high expression of lncRNA HEIH in peripheral blood of NSCLC patients can assist in the diagnosis of NSCLC and predict poor prognosis.
A total of 220 subjects were included in this study, including 70 healthy subjects, 70 patients with LUSC, and 80 patients with LUAD. As a biomarker, tumor marker CEA can play a role as a predictor and prognostic factor in cancer patients [23]. In the present study, serum CEA levels in LUSC and LUAD patients were higher than those in controls. Consistently, CEA has been identified as a biomarker to assist in the diagnosis of NSCLC [19, 20]. These results suggest that high serum CEA level can be used for the preliminary diagnosis of NSCLC.
Next, the expression of lncRNA HEIH in peripheral blood of LUSC and LUAD patients and healthy subjects was detected by qRT-PCR. LncRNA HEIH in peripheral blood of LUSC and LUAD patients was higher than that of healthy controls, while lncRNA HEIH expression between LUSC and LUAD groups had no significant difference. This result is consistent with previous reports that lncRNA HEIH is highly expressed in NSCLC tissues and cell lines [13]. Briefly, lncRNA HEIH level can be used as a potential diagnostic indicator for NSCLC, but it is not yet clear to distinguish LUSC from LUAD. To further study the relationship between lncRNA HEIH expression and clinical indicators in NSCLC patients, LUSC and LUAD patients were divided into a low-expression group and a high-expression group based on the median expression of lncRNA HEIH. In LUSC and LUAD patients, the lncRNA HEIH overexpression group had larger tumor size, higher tumor stage and higher CEA levels, and higher risk of lymph node metastasis and distal metastasis. Similarly, lncRNA-HEIH is highly expressed in melanoma tissues and cell lines, which is associated with late clinical stage and predicts poor prognosis in melanoma patients [14]. LncRNA HEIH high expression in gastric cancer patients is closely related to medium-high differentiation, distant metastasis, lymph node metastasis, and deeper tumor invasion [24]. Altogether, high expression of lncRNA HEIH is associated with poorer clinical indicators and higher cancer staging.
The tumor marker CEA has been well established as a biomarker for the diagnosis and treatment of NSCLC [17, 18]. We evaluated the diagnostic efficacy of lncRNA HEIH and CEA in patients with LSC and LUAD through ROC curve analysis, and the results showed that lncRNA HEIH had a high diagnostic efficacy in patients with NSCLC. Our paper may identify a more effective biomarker for NSCLC diagnosis.
Further, we analyzed the prognostic value of lncRNA HEIH in NSCLC. We divided LUSC and LUAD patients into a low-expression group and a high-expression group, based on the median expression of lncRNA HEIH in LUSC and LUAD, and then followed up the patients. The results showed that in LUSC and LUAD patients, the cumulative survival rate in the group with high expression of lncRNA HEIH was lower than that in the low expression group. These results suggest that high expression of lncRNA HEIH predicts poor prognosis in patients with NSCLC. The expression of HEIH is up-regulated in ovarian cancer tissues and cell lines, and high expression of HEIH indicates a poor prognosis [25]. Oesophageal squamous cell carcinoma patients with high lncRNA HEIH expression have poorer prognosis than those with low expression [26]. These results are consistent with the trend of our results.
In conclusion, the high expression of lncRNA HEIH in peripheral blood is helpful to the diagnosis and prognosis prediction of NSCLC, and may provide a new reference for evaluation of NSCLC clinically. However, due to the small number of cases and events included in this study, it is necessary to further expand the sample size to further clarify the diagnostic and prognostic ability of lncRNA HEIH. In addition, the role of lncRNA HEIH in the occurrence and development of NSCLC is still poorly understood, and further studies are needed. In future studies, we should carry out a larger multi-center study, expand the sample size and match the control to increase the credibility of the results. More studies are required to explore the molecular regulatory mechanism of lncRNA HEIH in the occurrence and development of NSCLC.