Analysis of Fifty Hotspot Mutations of Lung Squamous Cell Carcinoma in Never-smokers

Smoking is the major risk factor for lung squamous cell carcinoma (SCC), although a small number of lung SCCs occurs in never-smokers. The purpose of this study was to compare 50 hotspot mutations of lung SCCs between never-smokers and smokers. We retrospectively reviewed the medical records of patients newly diagnosed with lung SCC between January 1, 2011 and December 31, 2013 in the Seoul National University Hospital. Formalin-fixed, paraffin-embedded tumor samples were used for analysis of hotspot mutations. Fifty cancer-related genes in never-smokers were compared to those in ever-smokers. Of 379 lung SCC patients, 19 (5.0%) were never-smokers. The median age of these 19 patients was 67 years (interquartile range 57–73 years), and 10 of these patients were women (52.5%). The incidence rates of stage I, II, III, and IV disease in this group were 26.4%, 5.3%, 31.6%, and 36.8%, respectively, and sequencing was performed successfully in 14 cases. In the 26 lung SCC tumor samples (12 from never-smokers and 14 from ever-smokers) sequenced using personal genome machine, the most common mutations were in TP53 (75.0%), RAS (66.7%), and STK11 (33.3%), but mutations were also found in EGFR, KIT, and PTEN. The distribution of hotspot mutations in never-smokers was similar to that in ever-smokers. There was no significant difference in overall survival between the 2 groups. The 50 hotspot mutations of lung SCC in never-smokers were similar to those of ever-smokers.

The effects of secondhand smoke on chronic obstructive pulmonary disease in nonsmoking Korean adults

BACKGROUND/AIMS: Smoking is widely acknowledged as the single most important risk factor for chronic obstructive pulmonary disease (COPD). However, the risk of COPD in nonsmokers exposed to secondhand smoke remains controversial. In this study, we investigated the association of secondhand smoke exposure with COPD prevalence in nonsmokers who reported never smoking. METHODS: This study was based on data obtained from the Korean National Health and Nutrition Examination Surveys (KNHANES) conducted from 2008 to 2010. Using nationwide stratified random sampling, 8,596 participants aged > or = 40 years of age with available spirometry results were recruited. After selecting participants who never smoked, the duration of exposure to secondhand smoke was assessed based on the KNHANES questionnaire. RESULTS: The prevalence of COPD was 6.67% in participants who never smoked. We divided the participants who had never smoked into those with or without exposure to secondhand smoke. The group exposed to secondhand smoke was younger with less history of asthma and tuberculosis, higher income, and higher educational status. Multivariate logistic regression analysis determined that secondhand smoke did not increase the prevalence of COPD. CONCLUSIONS: There was no significant difference in the prevalence of COPD between participants who had never smoked with or without exposure to secondhand smoke in our study. Thus, secondhand smoke may not be an important risk factor for the development of COPD in patients who have never smoked.

Non-small cell lung cancer in never smokers: a clinical entity to be identified

OBJECTIVES: It has been recognized that patients with non-small cell lung cancer who are lifelong never-smokers constitute a distinct clinical entity. The aim of this study was to assess clinical risk factors for survival among neversmokers with non-small cell lung cancer. METHODS: All consecutive non-small cell lung cancer patients diagnosed (n = 285) between May 2005 and May 2009 were included. The clinical characteristics of never-smokers and ever-smokers (former and current) were compared using chi-squared or Student's t tests. Survival curves were calculated using the Kaplan-Meier method, and log-rank tests were used for survival comparisons. A Cox proportional hazards regression analysis was evaluated by adjusting for age (continuous variable), gender (female vs. male), smoking status (never- vs. ever-smoker), the Karnofsky Performance Status Scale (continuous variable), histological type (adenocarcinoma vs. non-adenocarcinoma), AJCC staging (early vs. advanced staging), and treatment (chemotherapy and/or radiotherapy vs. the best treatment support). RESULTS: Of the 285 non-small cell lung cancer patients, 56 patients were never-smokers. Univariate analyses indicated that the never-smoker patients were more likely to be female (68 percent vs. 32 percent) and have adenocarcinoma (70 percent vs. 51 percent). Overall median survival was 15.7 months (95 percent CI: 13.2 to 18.2). The never-smoker patients had a better survival rate than their counterpart, the ever-smokers. Never-smoker status, higher Karnofsky Performance Status, early staging, and treatment were independent and favorable prognostic factors for survival after adjusting for age, gender, and adenocarcinoma in multivariate analysis. CONCLUSIONS: Epidemiological differences exist between never- and ever-smokers with lung cancer. Overall survival among never-smokers was found to be higher and independent of gender and histological type.