OBJECTIVETo investigate the expression of transcription factor SOX4 in lung cancer tissues of female patients in Xuanwei area, Yunnan Province, and explore its correlation with clinicopathological characteristics and prognosis of the female patients.

METHODSReal-time PCR was applied on lung cancer specimens and their corresponding normal lung tissues from 96 female cases of Xuanwei area to assess the expression of SOX4 mRNA. Immunohistochemical staining was performed to investigate the SOX4 protein expression, and further to elucidate its correlation with clinicopathological characteristics and prognosis.

RESULTSThe expression level of SOX4 mRNA in the cancer tissues (2.53 ± 1.65) was significantly higher than that of matched normal tissues (1.43 ± 1.14, P = 0.003). Immunohistochemical staining showed that there were 53.1% (51/96) positive expression of SOX4 protein in the cancer tissue and only 26.0% (25/96) in matched normal tissue (P < 0.001). The expression of SOX4 protein had a significant correlation with clinical stage, lymph node metastasis and differentiation of tumor (P < 0.05). The survival analysis by Kaplan-Meier method showed that patients with positive expression of SOX4 protein, lymph node metastasis and advanced tumor stage had a significantly shorter median survival time (P < 0.05). Cox regression survival analysis showed that pathological grade was a significant independent factor affecting prognosis.

CONCLUSIONSThe expressions of SOX4 mRNA and protein are significantly up-regulated in Xuanwei female lung cancer patients. Patients with positive SOX4 expression have a shorter median survival time. SOX4 protein expression level combined with pathological grade can be used as a prognostic indicator of female lung cancer patients in Xuanwei area, Yunnan Province.