We found high HOTAIR expression in tumor tissues was significantly correlated with LNM and DM, and analysis showed a pooled OR of 3.18 (95% CI: 2.10-4.81, p<0.00001) and 3.93 (95% CI: 2.39-6.47, p<0.00001), respectively.
Long noncoding RNA HOX transcript antisense RNA (lncRNA HOTAIR) is overexpressed in many types of human cancers and is correlated with clinical stage and lymph node metastasis in oral squamous cell carcinoma (OSCC).
Moreover, in exploring the relationship between HOTAIR gene polymorphisms and the clinical status of only patients with OSCC who were non-betel quid chewers (excluding the advanced clinical stage), we found that rs920778 and rs4759314 were correlated with the development of large-size tumors (OR, 1.891; 95% CI, 1.027 to 3.484; P = 0.04) and increased lymph node metastasis (OR, 4.140; 95% CI, 1.785 to 9.602; P = 0.001), respectively.
The expressions of HOTAIR and p21 were determined to be related to lymph node metastasis, tumor node metastasis, Dukes staging, distant metastases, histological types, and the degree of differentiation.
For clinicopathological features, HOTAIR expression was positively associated with tumor size (odds ratio [OR]=2.19, 95% confidence interval [CI] 1.42-3.38, <i>P</i>=0.000) and lymph node metastasis (OR=6.04, 95% CI 3.51-10.42, <i>P</i>=0.000).
The results showed that high HOTAIR expression was associated with an advanced clinical tumor stage (OR = 3.90, 95% CI = 3.02-5.03, P < .001), lymph node metastasis (OR = 3.11, 95% CI = 2.15-4.49, P < .001), poor differentiation of the tumor (OR = 1.56, 95% CI = 1.01-2.41, P = .03), and worse prognosis (HR = 2.16, 95% CI = 1.73-2.69, P < .001) in different cancer types.
Multivariate Cox regression analysis confirmed expression of HOTAIR as an independent predictor of overall survival (<i>P</i> = 0.033), together with TNM stage (<i>P</i> = 0.002) and lymph node metastasis (<i>P</i> = 0.002).
TT genotype and T allele of HOTAIRrs920778 were significantly associated with a decreased ovarian cancer risk (p = 0.0004 and p < 0.0001, respectively), which associated with advanced tumor stage, lymph node metastasis and poor prognosis.
HOTAIR expression was significantly higher in cases with lymph node metastasis than in those without metastasis; in lowly differentiated and undifferentiated cases than in highly and moderately differentiated cases; and in stages III + IV cases than in stages I + II cases (P < 0.05).
The Meta-analysis results showed that high-expression of HOTAIR is significantly associated with clinicopathological features in gastric cancer patients, especially in the depth of tumor invasion, lymph node metastasis, vessel invasion, lymphatic vessel involvement and TNM stage, but there is no association between HOTAIR overexpression and other clinicopathological features.
Meta-analysis revealed that high HOTAIR expression was significantly correlated with poor OS (HR, 2.37; 95% CI, 1.80-3.11; P<0.00001) and positive LNM (RR, 1.96; 95% CI, 1.07-3.60; P=0.03).
This meta-analysis demonstrated that the incidence of lymph node metastasis in patients detected with high HOTAIR expression was higher than that in patients with low HOTAIR expression.
Lymphovascular invasion and lymph node metastasis were more common in the high level of HOTAIR group. si-HOTAIR significantly decreased invasiveness and migration. si-HOTAIR led to differential expression of epithelial to mesenchymal transition markers.
In gastric cancer, HOTAIR expression was found to be significantly associated with lymph node metastases (present vs. absent: OR 4.47, 95% CI: 1.88-10.63) and vessel invasion (positive vs. negative: OR 2.88, 95% CI: 1.38-6.04) without obvious heterogeneity.
Increased HOTAIR expression was significantly correlated with FIGO stage (P < 0.0001), lymph node metastasis (P < 0.0001), depth of cervical invasion (P < 0.0001), tumor size (P = 0.006) and age (P = 0.020), but not other clinical characteristics.
High expression of HOTAIR (tumor/normal ratio ⩾2) was detected in 17 patients (22.1%) and was frequently found in patients with advanced stage, lymph node metastasis or lymph-vascular invasion and short disease free interval.
Multivariate analysis revealed that HOTAIR expression (P = 0.003) is also an independent prognostic factor for comparison of TNM stage (P = 0.024) and lymph node metastasis (P = 0.010).