Clinicopathological characteristics and genetic analysis of pulmonary carcinoid tumors: A single-center retrospective cohort study and literature review.

Pulmonary carcinoid tumors, including typical and atypical carcinoids, are well-differentiated neuroendocrine tumors (NETs) that represent 1-2% of all lung cancer cases. In the present study, all cases of well-differentiated NETs diagnosed at Tianjin Medical University General Hospital (Tianjin, China) between 2006 and 2016 were reviewed, and 20 pulmonary carcinoid cases were identified. The clinical features of these cases were summarized, and the results of pathological and imaging examinations were collated. As a low-grade malignant pulmonary neoplasm, the molecular biological mechanism of pulmonary carcinoids is yet to be elucidated. To investigate the underlying molecular mechanisms behind pulmonary carcinoids and to determine an effective molecular targeted therapeutic strategy, next-generation sequencing (NGS) was performed using tissue samples from six patients to determine additional molecular biological characteristics that may help guide targeted therapy. A total of 27 somatic mutations in 21 genes were detected. Of note, mutations in the KIT proto-oncogene receptor tyrosine kinase, Erb-B2 receptor tyrosine kinase 4, MET proto-oncogene receptor tyrosine kinase and insulin-like growth factor 1 gene occurred in two out of six cases. Since treatments for advanced carcinoids are relatively ineffective, molecular profiling may contribute to the identification of novel treatments. In addition, the literature on mutations in pulmonary carcinoids was reviewed and available clinical information and features of this tumor type were summarized.