A meta-analysis of STAT3 and phospho-STAT3 expression and survival of patients with non-small-cell lung cancer

The prognostic role of signal transducer and activator of transcription 3 (STAT3) and phospho-STAT3 in non-small-cell lung cancer (NSCLC) remains controversial. To clarify its impact on survival, we performed a meta-analysis to quantitatively assess STAT3 and phospho-STAT3 expression on the prognosis of NSCLC.

Published studies were identified using a systematic and thorough literature search. To be eligible, a study had to investigate STAT3 or phospho-STAT3 expression rates of NSCLC patients in different characteristics and provide patient survival data.

A total of 17 retrospective trials were chosen for meta-analysis, including 1793 patients. The estimated pooled log HR (0.67, 95% CI: 0.57-0.77) of 9 trials (STAT3: log HR 0.71, 95% CI 0.38-1.04; phospho-STAT3: log HR 0.67, 95% CI 0.56-0.77) for NSCLC was statistically significant (P < 0.0001), suggesting that high STAT3 or phospho-STAT3 expression is a strong predictor of poor prognosis among patients with NSCLC. For the risk factors, pooled analysis of patients with STAT3 positivity, demonstrated a statistically significant OR (3.82, 95% CI: 2.37-6.16) between poorly differentiated carcinoma and well-moderately, OR (5.68, 95% CI: 3.16-10.21) between stage III-IV patients and stage I-II patients, and OR (3.41, 95% CI: 2.12-5.49) between patients with lymph node metastasis and patients without lymph node metastasis. However, pooled analysis of patients with phospho-STAT3 positivity only demonstrated a statistically significant OR (4.51, 95% CI: 1.57-12.96) between poorly differentiated carcinoma and well-moderately (P < 0.05).

High STAT3 or phospho-STAT3 expression is a strong predictor of poor prognosis among patients with NSCLC. The conclusion should be confirmed by large prospective studies with long-term follow-up.