A preliminary study on serum protein SP70 as a novel biomarker for the detection of non-small cell lung cancer

Abstract

Objective To evaluate whether the protein SP70 could be used as a serum biomarker for the diagnosis of non-small cell lung cancer （NSCLC）. Methods Polyclonal antibody was prepared by immunizing New Zealand rabbit with SPC-A1 cells.Sandwich ELISA was carried out by using newly-prepared polyclonal antibody（PcMb）coating assay plates，monoclonal antibody（McAb）NJ001 and HRP goat anti-mouse antibody as primary antibody and labeling antibody respectively.After optimizing the experiment conditions，serum from 175 lung cancer patients ［80 NSCLC adenocarcinoma，70 NSCLC squamous carcinoma and 25 small cell lung cancer（SCLC）］，25 benign lung disease（BLD）patients and 300 healthy controls （HC） were examined.CEA，NSE，CYFRA21-1 were measured by ECLIA for comparison. Results Positive rates of NSCLC adenocarcinoma，NSCLC squamous carcinoma，SCLC and BLD were 68.8%，51.4%，16.0% and 12.0% respectively，obviously higher than that of HC（7.3%）．NSCLC（adenocarcinoma，Squamous carcinoma） had significantly higher positive rate than SCLC（60.7% vs 16.0%，χ2=17.23，P<0.05）and BLD（60.7% vs 12.0%，χ2=20.41，P<0.05）.Among 68 NSCLC patients who had definite staging，positive rates at early stage（Ⅰ/Ⅱ，n=30） reached up to 76.7%.Meanwhile，positive rates of CEA，NSE and CYFRA21-1（32.7%，18.0% and 37.3%）were significantly lower than the targeting antigen to McAb NJ001 in NSCLC（60.7% vs 32.7%，χ2=23.63，P<0.05；60.7% vs 18.0%，χ2=57.22，P<0.05；60.7% vs 37.3%，χ2=16.34，P<0.05）. Conclusions It showed high positive rates of SP70 in the serum of NSCLC patients，which suggested that SP70 might be a potential valuable biomarker for the diagnosis of NSCLC.（Chin J Lab Med，2012,35：554-558） Key words: Lung neoplasms; Carcinoma;  non-small-cell lung; HSP70 heat-shock proteins; Tumor markers，biological; Enzyme-linked immunosorbent assay