Circulating long non-coding RNA AFAP1-AS1 is a potential diagnostic biomarker for non-small cell lung cancer

Background: Recent studies have indicated that long non-coding RNA actin filament-associated protein 1 antisense RNA 1 (IncRNA AFAP1-AS1) was increased in non-small cell lung cancer and associated with unfavorable patient prognosis. AFAP1-AS1 also participates in promoting invasion and metastasis in non-small cell lung cancer cells. However, the diagnosis value of serum AFAP1-AS1 in non-small cell lung cancer was unclear. In this study, we aimed to explore whether circulating AFAP1-AS1 can be used as a diagnostic biomarker for non-small cell lung cancer. Method: The serum AFAP1-AS1 expression level in 126 non-small cell lung cancer patients and 60 healthy controls was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The concentrations of serum cyfra21-1 were detected through chemiluminescence method using the Roche Cobas e601. Receiver operating characteristic curve analysis was applied to assess the diagnostic value of serum AFAP1-AS1 and cyfra21-1 in non-small cell lung cancer. Result The results demonstrated that AFAP1-AS1 expression level was significantly elevated in non-small cell lung cancer patients compared with that in normal controls (p = 0.000). Serum AFAP1-AS1 could be used as molecular marker for distinguishing non-small cell lung cancer patients from healthy people with an area under the curve of 0.759 (95% confidence interval = 0.692-0.826; p = 0.000). The combination of FAP1-AS1 and cyfra21-1 showed that the area under the curve was 0.860 (95% confidence interval = 0.808-0.912; p = 0.000). Further analysis found that high serum AFAP1-AS1 expression levels correlated with distant metastasis (p = 0.03), lymph node metastasis (p = 0.017), poor clinical stage (p = 0.019), and larger tumor size (p = 0.015). Furthermore, AFAP1-AS1 was significantly upregulated in positive distant metastasis group (p = 0.003), positive lymph node metastasis (p = 0.017), poor clinical stage group (p = 0.019), and larger tumor size group (p = 0.015). Conclusion: Serum AFAP1-AS1 could serve as an ideal combined biomarker for the diagnosis of non-small cell lung cancer.