I. Abdukader, Mª Pombo, S. Rodriguez- Segade,Alvaro Ruibal,F. Gude,Michel Herranz,P Aguiar, Serum carcinoembryonic antigen (CEA) levels are associated with the decrease/loss of p27 immunohistochemical expression in non-small cell lung cancer Annals of Clinical Oncology 2018 2674-3248 http://dx.doi.org/10.31487/j.ACO.2018.01.002 https://www.sciencerepository.org/serum-carcinoembryonic-antigen-CEA-levels-are-associated-with-the-decrease-loss-of-p27-immunohistochemical-expression-in-non-small-cell-lung-cancer_ACO-1-102 Abstract: Objective: to study the possible relation between immunohistochemical expression of p27 and serum carcinoembryonic antigen (CEA) levels in patients with non-small cell lung cancer (NSCLC) Material and Methods: The study group included 35 patients with NSCLC (15 squamous and 20 adenocarcinomas). Immunohistochemical expression of p27 was studied through the technique of tissuematrix using Tissue Arrayer Device, with monoclonal antibody M-T247 (Dako. Denmark). CEA serum levels were assayed using the “ECLIA” from Roche (Swiss). Results: P27 expression was noted in 27 cases (77,1%), being slightly (+) in 14 cases and strong (++) in 13 cases. CEA serum levels were higher (p:0,026) in + positive carcinomas (range: 2,2-570,7; median 7,6 ng/ml) than in ++ positive carcinoma (range: 1,5-35,1; median 2,7), but there were not differences between + positive and negative carcinomas. Likewise, there were statistically significant differences (p:0,043) between ++ positive group and -/+ group (r:0,8-766,7; median 6,3 ng/ml). Conclusions: Our results, preliminary do to the reduced number of patients included in the study, suggest that in patients with NSCLC, serum carcinoembryonic antigen levels can be associated with the decrease/loss of p27 immunohistochemical expression, important biological feature observed in various tumors, included lung carcinomas.Keywords: Non-small cell lung cancer (NSCLC), p27, carcinoembryonic antigen, CEA