Signal transducer and activator of transcription 3 overexpression promotes lymph node micrometastasis in early‐stage non‐small cell lung cancer

BACKGROUND: Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in several malignancies. Here, we define the correlation between STAT3 expression and lymph node micrometastasis of early‐stage non‐small cell lung cancer. Then we highlight some possibilities associated with developing a way to detect tumor micrometastasis and an anticancer drug that might therapeutically inhibit the STAT3 signaling pathway. METHODS: The samples were collected from 50 patients with early‐stage non‐small cell lung cancer and 50 patients with benign lung tumors. Mucin 1 mRNA expression was evaluated to determine lymph node micrometastasis status. STAT3 mRNA, STAT3 protein, and phosphorylated STAT3 protein expression were evaluated through reverse transcription polymerase chain reaction, western blot, and immunohistochemistry, respectively. Measurement data was represented as mean ± standard deviation, and the t‐rest or F‐test were used. The χ(2)‐test was used in enumeration data. Logistic regression analysis was carried out to determine the independent risk factors influencing lymph node micrometastasis. RESULTS: STAT3 mRNA and proteins expression were correlated with lymph node micrometastasis (P < 0.05). Logistic regression analysis revealed STAT3 protein overexpression and the differentiation degree of tumors were independent risk factors for lymph node micrometastasis. CONCLUSION: Overexpression of STAT3 might promote lymphatic micrometastasis of early‐stage non‐small cell lung cancer and might be a clinical predictor of lymph node micrometastasis.