Differential expression of NEAT1 and miR-506-3p in triple-negative breast cancer: potential tissue-based diagnostic biomarkers.

OBJECTIVES

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and HER2 expression, and is one of the most challenging cancers to treat. Non-coding RNAs have been identified as potential biomarkers for various diseases, including cancer. Identifying these biomarkers may facilitate early diagnosis and improve treatment strategies. Therefore, this study aimed to evaluate the non-coding RNAs NEAT1 and miR-506-3p expression levels in TNBC patients.

METHODS

Formalin-fixed, paraffin-embedded (FFPE) tumor tissues and paired adjacent non-tumor tissues were obtained from 35 TNBC patients. Total RNA was extracted, and the expression levels of NEAT1 and miR-506-3p were quantified by qPCR using GAPDH and U6 as internal controls, respectively. Relative expression was analyzed by the 2-ΔΔCt method. Statistical analyses included comparison of gene expression fold changes, assessment of associations with clinicopathological features, Spearman correlation analysis, and receiver-operating characteristic (ROC) curve analysis.

RESULTS

NEAT1 was significantly upregulated (≈eightfold, P < 0.0001) and miR-506-3p was markedly downregulated (≈fivefold, P < 0.0001) in tumor tissues compared to adjacent non-tumor samples. Elevated NEAT1 expression was significantly associated with the younger age group, necrosis, calcification status, larger tumor size, and vascular invasion, whereas no significant associations were observed with BMI, tumor grade, or lymph-node involvement (P > 0.05). MiR-506-3p expression showed no significant clinicopathological differences in subgroup analysis. A significant inverse correlation was observed between NEAT1 and miR-506-3p levels (rs = -0.33, P < 0.05). ROC curve analysis showed promising discriminatory performance for NEAT1 in the present cohort (AUC = 0.9563, 95% CI 0.9165-0.9961; estimated sensitivity = 1.00, specificity = 0.77) and moderate discriminatory performance for miR-506-3p (AUC = 0.7971, 95% CI 0.6946-0.8997). A logistic regression model combining both markers showed improved discrimination in this dataset (AUC = 0.9739).

CONCLUSION

Our findings suggest that NEAT1 and miR-506-3p exhibit opposite expression patterns in TNBC tissues and may serve as complementary tissue-based candidate diagnostic biomarkers. Their combined use showed improved discriminatory performance in this cohort; however, larger independent validation studies are required before a clinical diagnostic application can be proposed.