Expression Of Scavenger Receptor Class B Type ? In Lung Adenocarcinoma And Its Clinical Significance

Backgroung and ObjectiveLung cancer is one of the most common malignant tumors in the world with high morbidity and mortality.The cause of lung cancer is complicated,so far it is not completely clear.Currently,smoking is recognized as one of the most dangerous pathogenic factors in the world.Secondly,air pollution,occupational exposure,chronic lung disease and family history also increase the risk of lung cancer.Recent research has suggested that high-density lipoprotein(HDL)is implicated in modulating normal lung health and disease,including lung cancer.Higher circulating HDL levels are a favorable prognostic factor in non-small cell lung carcinoma(NSCLC).Scavenger receptor class B type I(SR-B1)is a glycoprotein on the surface of the cell membrane,which is mainly distributed in liver and nonsteroidal hormone of tissues and organs,such as the adrenal glands,testis,ovary,etc.SR-B1 is a high affinity receptor of HDL.Under the condition of the body's normal,it could involve in cholesterol reverse transportation by mediated high-density lipoprotein cholesterol ester(HDL-C),playing a role of resistance to atherosclerosis.When cancerous changes occur in the body,excess cholesterol can be transported to the tumor cells to complete their own proliferation.SR-B1 has been shown to be highly expressed in a variety of tumor cell lines,including liver,prostate,breast,colorectal,pancreatic,ovarian,and nasopharyngeal cancers.Moreover,SR-B1 is a crucial junction where breast and prostate tumor cells exploit HDL to ingest cholesterol for proliferative advantages,which is associated with tumor aggressiveness and poor clinical prognosis.However,the relationship between SR-B1 and lung cancer has not been elucidated.Epidemiological studies have shown that adenocarcinoma is the most common histopathological type of lung cancer in both smoking and non-smoking Asian populations.We evaluated SR-B1 expression using clinical specimens of lung adenocarcinoma.We aimed to assess the correlation between SR-B1 expression and clinicopathological factors of lung adenocarcinoma,as well as its influence on overall survival(OS).We hypothesized that SR-B1 could be used as a new prognostic biomarker and a potential therapeutic target for lung cancer.MethodsTo test these hypothese,we analyzed the expression of SR-B1 in a well characterized lung adenocarcinoma tissue microarray by immunohistochemistry,in 90 cancerous and 90 adjacent normal lung tissues.The relationship between SR-B1 and clinicopathological features and prognosis was analyzed by statistical method.Lung adenocarcinoma specimens and detailed pathological data were provided by Shanghai xinchao biotechnology co.,LTD.ResultsThe positive expression rate and expression level of SR-B1 in cancer tissues was significantly higher than that of adjacent tissues(P<0.001).The elevated SR-B1 expression was associated with American Joint Commercial on Cancer(AJCC)stage(P<0.001),T stage(P=0.038),N stage(P=0.002),and lymph node positivity(P<0.001).The Kaplan-Meier survival analysis indicated that patients with high SR-B1 expression had a shorter overall survival(P<0.001).On survival time of single factor analysis showed the SR-B1 expression level,AJCC stage,T stage,N stage,tumor size and lymph node positivity were related to the survival time.In this paper,a multivariate survival analysis model was used to analyze the meaningful variables by single factor survival analysis,suggesting that high SR-B1 expression was an independent predictor of poor prognosis in patients with lung adenocarcinoma(P=0.018).ConclusionThe results show that the scavenger receptor class B type ?(SR-B1)is overexpressed in lung adenocarcinoma tissues.High SR-B1 expression is associated with tumor aggressiveness and poor prognosis.In addition,high SR-B1 expression is an independent predictor of poor prognosis for patients with lung adenocarcinoma.These prompt that SR-B1 may participate in the development process of lung adenocarcinoma,and is a potential independent prognostic factor,even a therapeutic target in lung adenocarcinoma.