High expression of SRY-box transcription factor 30 associates with well differentiation, absent lymph node metastasis and predicts longer survival in nonsmall-cell lung cancer patients

The present study aimed to investigate SRY-box transcription factor 30 (SOX30) expression in nonsmall-cell lung cancer (NSCLC) tumor tissues and adjacent noncancerous tissues, and further explore the correlation of tumor SOX30 expression with clinical characteristics and survival profiles in patients with NSCLC. Totally, 365 patients with NSCLC who underwent resection were screened, and SOX30 expression was detected in their tumor tissues and adjacent noncancerous tissues via immunohistochemistry (IHC) assay, which was assessed by a semiquantitative method considering the multiplying staining intensity score and staining density score. According to the tumor SOX30 expression, patients were categorized as tumor SOX30 low (IHC score ≤3) and high (IHC score 4–12) patients, the latter were further divided into tumor SOX30 high+ (IHC score 4–6), high++ (IHC score 7–9), and high+++ (IHC score 10–12) patients. SOX30 was downregulated in NSCLC tumor tissues compared with adjacent noncancerous tissues. Meanwhile, tumor SOX30 high expression associated with well differentiation, absent lymph node metastasis, decreased TNM stage, but did not associated with age, gender, history of smoke and drink, hypertension, hyperlipidemia, diabetes, tumor size, or carcinoembryonic antigen level. Both accumulating disease-free survival and overall survival were the longest in tumor SOX30 high+++ patients, followed by tumor SOX30 high++ patients, and tumor SOX30 high+ patients, and the shortest in tumor SOX30 low patients. Besides, tumor SOX30 high expression was an independent predictor for longer disease-free survival and overall survival. Tumor SOX30 exhibits the potential to be a novel biomarker for survival prediction of patients with NSCLC.