Furthermore, low expression of miR-31-5p was highly correlated with tumor-node-metastasis (TNM) stage (I+II vs III+IV, p=0.001), T classification (T1 vs T2+T3+T4, p=0.036) and local lymph node metastasis (N1-N3 vs N0, p=0.002), but not distant metastasis (p=0.288).
Furthermore, low expression of miR-31-5p was highly correlated with tumor-node-metastasis (TNM) stage (I+II vs III+IV, p=0.001), T classification (T1 vs T2+T3+T4，p=0.036) and local lymph node metastasis (N1-N3 vs N0, p=0.002), but not distant metastasis (p=0.288).
In the observation group, the relative expression levels of miR-27a and miR-31 in patients with lymph node metastasis and distant metastasis were higher than those in patients without lymph node metastasis and distant metastasis (P<0.05).
Moreover, the decreased expression of miR-31 was demonstrated to be associated with lymph node metastasis, poor pT and pN stage, and invasion ability into lymphatic vessels as determined by the Mann-Whitney U test.
The data showed that miR-31 expression was down-regulated in 40 cases of gastric cancer tissues compared to the adjacent normal tissues, and low expression of miR-31 was associated with poor tumor differentiation, lymph node metastasis, advanced T stage and worse overall survival of gastric cancer patients.
MiR-31 was then validated as a marker for lymph node metastasis in an external validation cohort of 233 lung adenocarcinoma cases of the TCGA (P = 0.031, t test).