Smoking exposure, loss of forced expiratory volume in one second and the risk of lung cancer among patients with malignant disease who present with cardiac or pulmonary symptoms: a cross-sectional study

Roles of DNA repair enzyme OGG1 in innate immunity and its significance for lung cancer

Cytokines are pivotal mediators of the immune response, and their coordinated expression protects host tissue from excessive damage and oxidant stress. Nevertheless, the development of lung pathology, including asthma, chronic obstructive pulmonary disease, and ozone-induced lung injury, is associated with oxidant stress; as evidence, there is a significant increase in levels of the modified guanine base 7,8-dihydro-8-oxoguanine (8-oxoG) in the genome. 8-OxoG is primarily recognized by 8-oxoguanine glycosylase 1 (OGG1), which catalyzes the first step in the DNA base excision repair pathway. However, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, including NF-κB, to their cognate sites to enable expression of cytokines and chemokines, with ensuing recruitments of inflammatory cells. Hence, defective OGG1 will modulate the coordination between innate and adaptive immunity through excessive oxidant stress and cytokine dysregulation. Both oxidant stress and cytokine dysregulation constitute key elements of oncogenesis by KRAS, which is mechanistically coupled to OGG1. Thus, analysis of the mechanism by which OGG1 modulates gene expression helps discern between beneficial and detrimental effects of oxidant stress, exposes a missing functional link as a marker, and yields a novel target for lung cancer.

A lower level of forced expiratory volume in one second predicts the poor prognosis of small cell lung cancer

Background

The impact of impaired pulmonary function on the clinical outcome of small cell lung cancer (SCLC) has not been examined. The objectives of this study were to compare the clinical characteristics and prognosis of SCLC patients with and without impaired pulmonary function and investigate predictors related to the pulmonary function of mortality in SCLC patients.

Methods

This is a retrospective multicenter study performed between January 2011 and December 2015. In all, 170 SCLC patients that were treated with chemotherapy and/or radiotherapy and had a pulmonary function test (PFT) were enrolled. Patients were divided into the chronic obstructive pulmonary disease (COPD) group and the non-COPD group. The overall survival (OS) was compared and predictors of worse OS were analyzed.

Results

COPD was present in 54.7% of all SCLC patients. There were no differences in the clinical characteristics and treatment strategies between the COPD and non-COPD groups. OS (log-rank test, P=0.103) was not different between the COPD and non-COPD groups. In a multivariate analysis using a Cox regression model, extensive disease (ED) [hazard ratio (HR) =2.863; 95% CI: 1.787-4.587] and low forced expiratory volume in 1 second (FEV₁) <80% (HR =1.854; 95% CI: 1.077-3.192) were independent risk factors for shorter survival. In a subgroup multivariate analysis, a FEV₁ less than 80% (HR =5.631; P=0.018) was independently associated with poor OS in patients with ED.

Conclusions

A low FEV₁, not COPD, was a predicting factor for poor treatment outcomes in SCLC patients.