Objective To investigate the expression of maternal embryonic leucine zipper kinase (MELK) in esophageal squamous cell carcinoma and its significance. Methods The surgical resection specimens of 139 patients with esophageal squamous cell carcinoma who were admitted to Peking University Cancer Hospital from August 2009 to July 2013 were selected. MELK expression in esophageal squamous cell cancer tissues was detected by immunohistochemistry. The relationship between MELK expression and clinicopathological characteristics of patients was analyzed. MELK expression in 6 esophageal squamous cell carcinoma cell lines (ECA109, KYSE150, KYSE30, KYSE70, KYSE180 and KYSE510) was tested by Western blot, and the cell line with high MELK expression was selected, and the expression of MELK was knocked down by lentiviral infection. The effect of MELK on tumor cell migration and invasion was examined by Transwell method, and the effect of MELK on cell proliferation was verified by CCK-8 method. Results MELK is highly expressed in 100 cases (71.9％) of esophageal squamous cell carcinoma, and the positive expression rate of MELK in patients with stage T3-T4 was higher than that in patients with stage T1-T2 (χ2=4.702, P= 0.030). The poor differentiation and lymph node metastasis inclined to higher MELK positive expression rate, but the difference was not statistically significant (χ2 = 2.761, P= 0.097; χ2= 0.994, P=0.319). MELK was highly expressed in ECA109 and KYSE150 cells. The Transwell test results showed that the number of migrating cells of EEL109 and KYSE150 cells in the MELK knockdown group was decreased when compared with the negative control group [(77±10) cells vs. (126±8) cells, t=6.56, P<0.05;(37±4) cells vs. (105 ±3) cells, t= 24.27, P< 0.05], and the number of invading cells was decreased [(47 ±7) cells vs. (154±9) cells, t= 17.08, P< 0.05; (37±2) cells vs. (184±4) cells, t= 54.09, P< 0.05]. CCK-8 proliferation studies showed that the proliferation of ECA109 and KYSE150 cells in the MELK knockdown group was inhibited (both P< 0.05). Conclusions The high MELK expression in patients with esophageal squamous cell carcinoma is associated with T stage. High expression of MELK can promote the proliferation and invasion of tumor cells in esophageal squamous cell carcinoma.

BACKGROUND: Bronchopleural fistula (BPF) is one of the most serious and rare postoperative complications, especially the bronchial stump fistula after lobectomy/pneumonectomy. Common treatment options include conservative medical treatment combined with surgery. However, due to the delayed healing of the fistula, the chest cavity continues to communicate with the outside world, and the patient is prone to complicated with severe thoracic infection and respiratory failure, so that the physical condition can hardly tolerate the second surgical procedure. Endoscopic treatment provides a new option for the treatment of this complication. METHODS: A case of right pulmonary squamous cell carcinoma was admitted to the Department of Thoracic Surgery II, Peking University Cancer Hospital in June 2016. The diagnosis and treatment was retrospectively analyzed, and the literature was reviewed. RESULTS: A 65 year old male patient was admitted to hospital because of "cough with blood in sputum for 3 months". Chest computed tomography (CT) showed soft tissue density mass shadow in the right lower lobe. A tumor could be seen in the opening of the right middle lobe and basal segment of lower lobe. Biopsy confirmed squamous cell carcinoma. Diagnosis consideration: squamous cell carcinoma of the middle and lower lobe of the right lung (cT2aN2, IIIa). Patients received gemcitabine plus cisplatin neoadjuvant chemotherapy for 2 cycles, and the effect of chemotherapy showed stable disease (SD). Four weeks after chemotherapy, the patient underwent video-assisted thoracic surgery (VATS) assisted right middle and lower lobectomy and mediastinal lymph node dissection. On the 5th day after operation, the patient developed acute respiratory distress syndrome (ARDS) and was transferred to intensive care unit (ICU) again after endotracheal intubation. On the 7th day after operation, the patient developed a right intermediate trunk bronchial stump fistula, but due to ARDS, the patient's physical condition could not tolerate the second operation. Under the support of extracorporeal membrane oxygenation (ECMO), a membrane covered, expandable, hinged stent was inserted into the intermediate trunk bronchial stump through rigid bronchoscope, and was successfully blocked. Due to no improvement in ARDS and irreversible pulmonary interstitial fibrosis, the patient received double lung transplantation successfully after systemic anti-infection treatment. CONCLUSIONS Endoscopic implantation of covered stent is a simple, safe and effective method for closure of bronchial stump fistula. When the patient's clinical situation is not suitable for immediate surgery, endoscopic stent implantation can be used as a preferred treatment method to create opportunities for follow-up treatment.

BACKGROUND: IIIa-N2 non-small cell lung cancer was significant different in survival, although N stage of lung cancer based on anatomic location of metastasis lymph node. Lymph node ratio considered of prognostic factor might be the evaluation index for IIIa-N2 non-small cell lung cancer prognosis. Therefore, the aim of the study was to evaluate the correlation between lymph node ratio and clinicopathological features and prognosis of IIIa-N2 non-small cell lung cancer prognosis. METHODS: A total of 288 cases of pathological IIIa-N2 non-small cell lung cancer were enrolled who received radical resection at the Department of Thoracic Surgery II, Peking University Cancer Hospital from January 2006 to December 2016. The univariate analysis between clinicopathological variables and lymph node ratio used Pearson's chi-squared test. Cox regression was conducted to identify the independent prognosis factors for IIIa-N2 non-small cell lung cancer. RESULTS: There were 139 cases in the lower lymph node ratio group, another 149 cases in the higher lymph node ratio group. Adenocarcinoma (χ²=5.924, P=0.015), highest mediastinal lymph node metastasis (χ²=46.136, P<0.001), multiple-number N2 metastasis (χ²=59.347, P<0.001), multiple-station N2 metastasis (χ²=77.387, P<0.001) and skip N2 lymph node metastasis (χ²=61.524, P<0.001) significantly impacted lymph node ratio. The total number of lymph node dissection was not correlated with the lymph node ratio (χ²=0.537, P=0.464). Cox regression analysis confirmed that adenocarcinoma (P=0.008), multiple-number N2 metastasis (P=0.025) and lymph node ratio (P=0.001) were the independent prognosis factors of disease free survival. The 5-year disease free survival was 18.1% in the higher lymph node ratio group, and 44.1% in the lower. Lymph node ratio was the independent prognosis factor of overall survival (P<0.001). The 5-year overall survival was 36.7% in the higher lymph node ratio group, and 64.1% in the lower. CONCLUSIONS Lymph node ratio was correlative with the pathology, highest mediastinal lymph node metastasis, multiple-number N2 metastasis, multiple-station N2 metastasis and skip N2 lymph node metastasis. Lymph node ratio was the independent prognosis factor for IIIa-N2 non-small cell lung cancer.