Expression Of ATF5 In Lung Cancer And Its Clinical Significance

Objective:Activating transcription factor 5 (ATF5) is a transcription factor from the ATF/cAMP responsive element binding protein (ATF/CREB) family, and its positive expression in many malignant tumors, which has been proven by many researches, is associated with tumor differentiation and staging and may contribute to the occurrence and development of tumors. However, there are few studies focusing on ATF5 in lung cancer. Through the observation of ATF5 expression in lung cancer tissues, the author analyzes the implications for its positive expression in the present research and provides basis for further exploring the potential role of ATF5 in tumors. Methods:A total of 60 lung cancer specimens and normal lung tissues near tumors obtained from patients undergoing thoracic surgery at Subei People’s Hospital of Jiangsu Province from January 2009 to December 2013 were collected as complete patient data. ATF5 expression in 60 lung cancer tissues and normal lung tissues near tumors were detected with immunohistochemical method. These patients were divided into various groups according to sex (male or female), age (≤60 or>60), smoking or non-smoking, pathological type (adenocarcinoma, squamous cell carcinoma or small cell lung cancer), pathological stage (Stage I+II or Ⅲa), lymphatic metastasis or not, and differentiated degree (poorly or moderately+highly). SPSS 17.0 statistical software was employed. The experimental data were treated with χ2test. ATF5 expression in lung cancer and normal lung tissues near tumors was observed to identify whether there were differences between different groups. Also, an analysis was conducted on the correlation between its expression and carcino-embryonic antigen (CEA), one of the clinically common tumor indicators, thus synthetically discussing the clinical significance of ATF5 expression.Results:1. Positive ATF5 expression in lung tissues was mostly located in the cytoplasm, demonstrating diffuse or focal yellow or brown granular staining.2. ATF5 expression in lung cancer tissues and normal lung tissues:ATF5 was expressed in 5 of 60 normal lung tissues (8.33%), all of which were weak positive; ATF5 expression was found in 42 of 57 non-small cell lung cancers (NSCLCs) (73.7%,40.5% for weak positive,45.2% for positive,14.3% for intense positive), and there were statistically significant differences between these lung cancer tissues and normal lung tissues (χ2=51.942,P<0.01). However, since chemoradiotherapy is the treatment of choice for small cell lung cancer (SCLC), only a few of surgical patients were enrolled. In this study, ATF5 expression (weak positive) was noted in 2 of 3 cases with SCLC (66.7%), but the limited number of cases led to their exclusion from the final relevant clinical value analysis.3. The correlations between ATF5 expression in NSCLC and clinical and pathological indexes:ATF5 expression in NSCLC was irrelevant to sex, age, smoking or non-smoking, pathological stage, and lymphatic metastasis or not (all.P>0.05), but relevant to pathological type (χ2=8.879,P<0.05) and differentiated degree (/=9.321, P<0.05):ATF5 expression in adenocarcinoma (27/32,84.4%) was greatly higher than that in squamous carcinoma (15/25, 60%); ATF5 expression in the poorly differentiated group (14/14,100%) was greatly higher than that in the highly+moderately differentiated group (28/43,65.1%), showing statistically significant difference.4. The relationship between ATF5 expression in NSCLC and CEA:Among the 57 patients with NSCLC in this study,18 showed abnormal CEA (>5ng/ml) (18/57,31.6%), while most of ATF5 expression in patients presenting with abnormal CEA (17/18,94.4%) was remarkably higher than that in patients with normal CEA (25/39,64.1%), and there was a statistically significant difference (P<0.05), suggesting ATF5 expression was associated with abnormal CEA.Conclusions:1. ATF5 expression is found in lung cancer tissues and much higher than that in normal lung tissues, suggesting that ATF5 is very likely to be a novel lung cancer marker.2. ATF5 expression in NSCLC is related with pathological type, and its relation with adenocarcinoma is stronger than that with squamous cell carcinoma, making it possible to further study its role in the pathogenesis of lung cancer especially adenocarcinoma in lung cancer. ATF5 would probably become a new target for targeted therapy of lung cancer.3. ATF5 expression in NSCLC in the poorly differentiated group is much higher than that in the highly+ moderately differentiated groups and is related with CEA,suggesting that ATF5 is associated with tumor malignant degree and disease progression,and it is of certain clinical value in evaluating disease and prognosis.