Urologic Oncology: Seminars and Original Investigations ] (2017) ∎∎∎–∎∎∎ Original article Experimental validation of the complement protein C3a down expression in the plasma of patients with squamous cell carcinoma of the penis Paulo Ornellas, M.D. a,b,c , Marilza de M. Ribeiro-Carvalho, Ph.D. c , Antonio Augusto Ornellas, Ph.D., M.D. a,b,d, * , Luciano Scherrer, M.S. e , Leandro Koifman, M.D. b , Fulvio Magni, Ph.D. f , Maria Helena Ornellas, M.D., Ph.D. c , Gilda Alves, Ph.D. c,g a Department of Urology, Mário Kröeff Hospital, Rio de Janeiro, Brazil b Department of Urology, Souza Aguiar Hospital, Rio de Janeiro, Brazil c Programa de Pós-Graduação em Ciências Médicas, Circulating Biomarkers Laboratory, Department of Pathology, Rio de Janeiro State University, Rio de Janeiro, Brazil d Department of Urology, Brazilian National Cancer Institute, Rio de Janeiro, Brazil e Department of Engineering and Production, Faculdades Kennedy, Belo Horizonte, Brazil f Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy g Research Coordination, Brazilian National Cancer Institute, Rio de Janeiro, Brazil Received 11 January 2017; received in revised form 15 February 2017; accepted 2 May 2017 Abstract Objectives: We have previously shown the importance of the complement system in differentiating between patients with squamous cell carcinoma of the penis (SCCP) and controls. These patients had low expression of C3a and C4 fragments. Therefore, in this study, we investigated the complement protein C3a as a potential circulating biomarker in these patients by a commercially available enzyme-linked immunosorbent assay (ELISA) test. Patients and methods: Plasma samples from 39 patients with SCCP, 15 patients with prostate cancer, and 50 healthy male subjects were evaluated using the ELISA—Bioscience OptEIA Kit human anti-C3a (BD). The nonparametric Mann-Whitney test was used for comparison of means among the groups. Results: The complement protein C3a was found down expressed in patients with SCCP (P o 0.05) in comparison to either subjects with good health or subjects with prostate cancer. Conclusion: Experimental validation of the down expression of C3a was well succeeded using a commercial ELISA kit. Complement system fragment C3a is down expressed in patients with SCCP. Besides, C3a is also low expressed in the plasma of patients with initial prostate cancer when compared to healthy subjects. These results suggest that the innate immune response might be suppressed in patients with these malignancies. r 2017 Elsevier Inc. All rights reserved. Keywords: Circulating biomarker; Plasma; Tumor microenvironment; Penile cancer; Human complement C3a-desArg/C4a-desArg; Enzyme-linked immunosorbent assay (ELISA) 1. Introduction Squamous cell carcinoma of the penis (SCCP) represents 95% of the penile cancers. SSCP is considered a rare disease in developed countries. On the contrary, in underdeveloped and emerging countries, SSCP is a neglected type of cancer, reaching up to 10% of male neoplasms in some areas [1,2]. The incidence of carcinoma of the penis varies according to circumcision practice, hygienic standard, phimosis, number of sexual partners, human papillomavirus infections, expo- sure to tobacco products, and other factors [2,3]. Thus, inflammatory processes can be directly associated with this type of cancer [4]. http://dx.doi.org/10.1016/j.urolonc.2017.05.002 1078-1439/r 2017 Elsevier Inc. All rights reserved. This work was financially supported by Programa de Oncobiologia and FAPERJ (APQ1 E-26/111.336/2013), Rio de Janeiro, Brazil. * Corresponding author. E-mail address: ornellasa@hotmail.com (A.A.Ornellas).