Serum lncRNA HOTAIRM1, but not miR-182-5p, as a Potential Non-Invasive Biomarker for Endometrial Cancer

Background: Endometrial cancer (EC) is the second most common gynecological malignancy and remains a major contributor to morbidity and mortality among women worldwide. Current diagnostic and prognostic tools have limited accuracy, highlighting the need for reliable, non-invasive biomarkers. Non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), have emerged as promising candidates. This study aimed to investigate serum lncRNA HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1) and miR-182-5p expression levels in EC and evaluate their diagnostic value and association with clinicopathological features. Methods: This prospective cohort study analyzed serum samples that were prospectively collected from 73 women with histologically confirmed EC and 76 controls with non-malignant gynecological conditions. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to quantify serum lncRNA HOTAIRM1 and miR-182-5p expression levels. Associations with clinicopathological parameters and diagnostic performance were evaluated. Results: Serum expression levels of lncRNA HOTAIRM1 were significantly higher in EC patients (median [interquartile range (IQR)]: 1.36 [0.74–3.37]) than in controls (1.03 [0.58–2.03]; p = 0.043), whereas miR-182-5p levels showed no significant difference (p = 0.327). Receiver operating characteristic (ROC) curve analysis demonstrated that serum lncRNA HOTAIRM1 had high specificity (93.2%) but low sensitivity (29.6%) for EC diagnosis. No significant associations were identified between either biomarker or clinicopathological variables (p > 0.05). Conclusions: This study provides one of the first evaluations of circulating lncRNA HOTAIRM1 and miR-182-5p in serum samples from patients with EC. Our findings suggest that serum lncRNA HOTAIRM1, but not miR-182-5p, may serve as a potential non-invasive biomarker for EC. Although its limited sensitivity restricts its role as a standalone diagnostic tool, its high specificity supports potential clinical relevance. These preliminary results should be interpreted with caution, as they represent an initial exploratory analysis of circulating lncRNA HOTAIRM1 and miR-182-5p in EC.