Objective To study the diagnostic value of Sox2 mRNA transcription level in bronchoscopic biopsy specimens from lung cancer patients. Methods The expression of Sox2 mRNA was detected using RT-PCR from 100 hu-man lung cancer biopsy and 18 non-cancer lung biopsy through bronchoscopy. The expression of Sox2 protein was examined by immunohistochemistry from 50 cases of lung cancer biopsy, 32 cases of benign lung lesions and 18 cases of pericarcino-matous normal lung tissues. Then the relationships between Sox2 mRNA transcription level and lung cancer clinical patho-logical parameters were analyzed to test the diagnostic value of Sox2 transcription level. Results The transcription of Sox2 mRNA and its protein expression level were significantly higher in lung cancer than that in benign pulmonary disease tissues (P＜0.05). The transcription of Sox2 mRNA was not correlated with age, gender, histology, lymph node metastasis, TNM stage and differentiation of lung cancer patients (P>0.05). The Sox2 mRNA yielded an area of 0.748 under the ROC curve with the sensitivity of 85.0%and the specificity of 61.1%, taking the cut-off value of 0.513. Conclusion The Sox2 mRNA might be a useful diagnostic marker for lung cancer.

Objective To detect the expressions and clinical significance of Nanog and CD44 protein in lung cancer. Methods The expressions of Nanog and CD44 were detected by immunohistochemistry in 50 cases of lung cancer, 32 cases of benign lesion lung tissue and 18 cases of paraneoplastic normal lung tissue. Then their relationships with clinicopathological factors were analyzed. Results The expression of Nanog in lung cancer was significantly higher than those in benign lesion lung tissue and paraneoplastic normal lung tissue (P < 0.05). There was no significant difference of the expression of CD44 among the three groups (P > 0.05). The expressions of Nanog and CD44 in squamous cell carcinomas were higher than those in adenocarcinomas and small cell lung carcinomas (P < 0.05). The expressions of Nanog and CD44 were significantly correlated with lymph node metastasis (P < 0.05), but were not correlated with age, gender, tumour size, TNM stage and differentiation of lung cancer (P>0.05). The positive correlation was also noted between the expressions of Nanog and CD44 in lung cancer (r = 0.564, P < 0.05). Conclusion Nanog and CD44 proteins may participate in the genesis and progression of lung cancer. Nanog protein is a potential diagnostic marker and therapeutic target for lung cancer.

OBJECTIVE To prepare spider fibroin membrane loaded with Periplaneta americana extract， and investigate its characterization， in vitro drug release property and cytotoxicity. METHODS Using natural spider silk collected from Chilobrachys guangxiensis as raw material， P. americana extract as model drug， the drug-loaded spider fibroin membrane （hereinafter referred to as drug-loaded membrane） was prepared by solvent casting method. The material matrix spider fibroin membrane without P. americana extract （hereinafter referred to as blank membrane） was prepared with same method. The membrane structure was characterized by static water contact angle， Fourier infrared chromatography， X-ray diffraction and scanning electron microscopy from different angles； drug release characteristics in artificial saliva were simulated in vitro to evaluate the drug sustained-release performance. MTT assay was adopted to validate the cytotoxicity of drug-loaded membrane. RESULTS The drug-loaded membrane was prepared， and the static water contact angle was less than 90°， which was less than that of blank membrane. The drug-loaded membrane showed the characteristic absorption peak to polypeptide of P. americana extract at 1 500-1 700 cm－1. X-ray diffraction and scanning electron microscopy also proved that the drug was successfully loaded into the pellicle. The release time of the pellicle in artificial saliva was more than 200 min. The MTT test results showed that the cell proliferation rates of blank membrane and drug-loaded membrane were 84.6% and 79.4% （both greater than 70%）， respectively， without significant potential cytotoxicity. CONCLUSIONS Drug-loaded membrane prepared with natural spider silk has a certain sustained-release effect in artificial saliva， which can be further developed as a drug sustained-release carrier with excellent biological characteristics and biocompatibility.