Circulating long noncoding RNA GAS5 as a potential biomarker in breast cancer for assessing the surgical effects.

Long noncoding RNAs (lncRNAs) play a vital role in tumorigenesis. Until now, the value of circulating lncRNAs in the diagnosis of breast cancer (BC) has remained unknown. Here, we have explored the clinical significance of lncRNAs GAS5 and H19 in BC patients. Total RNA in the plasma was extracted from 90 preoperative BC patients, 39 postoperative BC patients, and 76 healthy controls. The expression levels were measured by quantitative real-time PCR. The potential associations between GAS5, H19 levels, and patients' clinical characteristics were analyzed. No significant differences were found between the BC patients and the healthy controls in the expression levels of GAS5 (P = 0.441) and H19 (P = 0.554), normalized by GAPDH. Plasma GAS5 exhibited correlations with the Ki67 proliferation index in 90 preoperative BC patients (P = 0.012). Compared with paired preoperative plasma, the postoperative levels of GAS5 and H19 significantly decreased in 71.8 % of BC patients (28/39) and 82.1 % of BC patients (32/39), respectively. Analysis in the 39 paired preoperative and postoperative plasma samples showed that lower GAS5 levels appeared in the patients with a high Ki67 proliferation index before surgery (P = 0.012) and the patients with a positive lymph node metastasis state after surgery (P = 0.029). Plasma lncRNA GAS5 may have the potential to assess the surgical effects and prognosis for BC patients.