Chronic airway inflammation plays an important role in the occurrence and development of chronic obstructive pulmonary disease and lung cancer[20]. Siemes et al. followed up a group of more than 7000 people without malignant tumors for about 10 years. The results showed that the possibility of cancer increased when CRP (C-reactive protein) > 3mg/dl[21]. Danish researchers measured baseline CRP, fibrinogen and leukocyte levels in 8656 patients with COPD and followed them up for 5 years[22]. It was found that patients with elevated inflammatory indexes had a four-fold increased risk of lung cancer. PRISm was previously considered to be an unclassified and restricted lung function impairment disease[23]. Like COPD, it has the change of decreased FEV1 and chronic airway inflammation. Patients with PRISm are more likely to be male, smoker, and tend to have a higher basis of metabolic syndrome and cardiovascular and cerebrovascular diseases[24, 25].A recent study from South Korea demonstrated that NSCLC patients with PRISm had a worse survival prognosis than those with COPD or normal lung function[6]. In our study, we found that patients with PRISm or COPD exhibited poorer disease-free survival (DFS) than the normal lung function group. When comparing the overall survival (OS) of NSCLC patients with different lung function states in the three groups, there was only significant difference between COPD group and normal lung function group. The reason why it is not completely consistent with previous studies may be related to the baseline level differences of the patients, such as the selected population, sample size, age and tumor stage.
In the occurrence, development and prognosis of chronic lung inflammation and lung tumors, systemic inflammatory indicators, such as NLR, LMR, PLR and EOS, can play a critical role in innate and adaptive immunity as effective markers[26, 27]. Neutrophils are constantly recruited and activated in COPD lungs, producing a large number of oxidants such as ROS, causing DNA oxidative damage and increasing the incidence of lung tumors. Neutrophil elastase secreted by neutrophils can directly activate TLR4 signaling pathway, thus promoting the expression of CXCL8 in bronchial epithelial cells and the production of mucin by activating EGFR[28, 29]. From the perspective of adaptive immunity, COPD pulmonary inflammation affects the ability of CD8+ cells to clear tumor cells, and impacts the balance of Th1/Th2, the proportion of regulatory T cells and Th17 cells, and the expression of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) in CD8+ T cells, resulting in cell cycle arrest and T cell inactivity[30]. A study including 3,656 patients showed NLR to be potentially a useful biomarker to predict the poor prognosis for NSCLC [31]. The research of Lin et al. indicated that LMR was potentially used as an independent prognostic factor for survival in previously untreated metastatic NSCLC[32]. In a study comprising 3430 patients, Gu et al. found that PLR was associated with unfavorable survival in advanced NSCLC[33]. Similarly, peripheral EOS was reported to be connected with the effect of immune checkpoint inhibitor treatment in NSCLC patients[34]. In our study, we found that there were differences to various degree of serum inflammatory indicators in different lung function groups. The coexistence of PRISm or COPD influenced the systemic inflammatory response of NSCLC patients and these results provided a basis for the individualized treatment and management of NSCLC patients with pulmonary dysfunction.
Testin is a protein expressed in a wide range of normal human tissues and locates in the cytoplasm along stress fibers being recruited to focal adhesions[35]. Latest reports indicated that Testin served as a tumor suppressor in the carcinogenesis of multiple types of cancers, including colorectal cancer[36], childhood acute lymphoblastic leukaemia[37],nasopharyngeal carcinoma[17], breast cancer[38] and gastric cancer[39], however the mechanism of loss of Testin expression is still unknown. Testin participates in the processes of cell cycle, tumor growth, apoptosis, epithelial-mesenchymal transition, angiogenesis, and metastasis[18], suggesting its potential usage in the diagnosis and therapy of cancer. Our previous study identified that Testin expression was reduced in NSCLC cell lines and overexpression of Testin significantly inhibited tumor growth of NSCLC both in vitro and in vivo[19]. In the present study, our results revealed that although there was no difference in Testin expression among the three groups of different pulmonary function, Testin expression correlated with poor clinicopathological parameters of NSCLC patients, including pN status, TNM stage and tumor invasion. Furthermore, patients with relative higher expression of Testin survive longer than those with lower ones and Cox regression analysis indicated that Testin served as an independent risk factor of prognosis for NSCLC patients. Our study adds the understanding of Testin in NSCLC and provides potential markers for the diagnosis and treatment of NSCLC.
In conclusion, this study assessed the pre-operational clinicopathological characteristics of NSCLC patients with PRISm or COPD. NSCLC patients with different lung function exerted differences in systemic inflammatory response and prognosis. Testin was clinically relevant with NSCLC and served as a promising marker for predicting prognosis of operatable NSCLC patients.