Prognosis of mucoepidermoid carcinoma of the bronchi

BACKGROUND: Mucoepidermoid cancer is exceptional in the respiratory tract, accounting for only 0.2% of primary lung cancers.CASE REPORTS: We report three cases of mucoepidermoid carcinoma. The inaugural signs were hemoptysia in a 10-year-old child, recurrent lower respiratory tract infections in a 13-year-old child, and dyspnea with chest pain in a 32-year-old adult. Bronchial fibroscopy disclosed a proximal endobronchial tumor in all three patients. Pathology study of the operative specimen identified low-grade malignant mucoepidermoid carcinoma in the two children and high-grade malignant mucoepidermoid carcinoma in the adult. Surgical resection was performed for the pediatric cases. Outcome was favorable with recurrence-free survival at eight years in the first child. The surgical resection was less radical in the second child due to locoregional extension. This child was lost to follow-up. The clinical course was rapidly fatal in the third patient who presented metastatic spread at diagnosis and died one month later.DISCUSSION: The prognosis of mucoepidermoid tumors of the bronchi is closely related to tumor grade and extension at diagnosis. Unlike high-grade mucoepidermoid carcinoma, the progression of low-grade tumors, which predominate in children, is generally slow, enabling good prognosis if diagnosis is established early. Early search for these tumors in patients presenting chronic or recurrent respiratory manifestations would avoid late diagnosis and improve prognosis.     

Bronchorelaxation of the human bronchi by CFTR activators

The airway functions are profoundly affected in many diseases including asthma, COPD and cystic fibrosis (CF). CF the most common lethal autosomal recessive genetic disease is caused by mutations of the CFTR (Cystic Fibrosis transmembrane Conductance Regulator) gene, which normally encodes a multifunctional and integral membrane cAMP regulated and ATP gated Cl⁻ channel expressed in airway epithelial cells.Using human lung tissues obtained from patients undergoing surgery for lung cancer, we demonstrated that CFTR participates in bronchorelaxation. Using human bronchial smooth muscle cells (HBSMC), we applied iodide influx assay to analyze the CFTR-dependent ionic transport and immunofluorescence technique to localize CFTR proteins. Moreover, the relaxation was studied in isolated human bronchial segments after pre-contraction with carbachol to determine the implication of CFTR in bronchodilation.We found in HBSMC that the pharmacology and regulation of CFTR is similar to that of its epithelial counterpart both for activation (using forskolin/genistein or a benzo[c]quinolizinium derivative) and for inhibition (CFTR_inh-172 and GPinh5a). With human bronchial rings, we observed that whatever the compound used including salbutamol, the activation of muscular CFTR leads to a bronchodilation after constriction with carbachol.Altogether, these observations revealed that CFTR in the human airways is expressed in bronchial smooth muscle cells and can be pharmacologically manipulated leading to the hypothesis that this ionic channel could contribute to bronchodilation in human.