Tissue-polypeptide-specific antigen levels in diabetic patients with normal and pathological biochemical profiles Javier Rodriguez a,b , Rubén Varela-Calviño a , Manuel Garrido Outeiriño a,b , Santiago Rodríguez-Segade a,b , Felix Camiña a, ⁎ a Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Spain b Clinical Biochemistry Division, University Clinical Hospital, Santiago de Compostela, Spain Received 18 May 2006; received in revised form 19 October 2006; accepted 5 November 2006 Available online 5 December 2006 Abstract Objectives: To identify causes for the raised TPS levels seen in diabetic patients. Design and methods: Relationships between TPS levels and biochemical markers for glycaemic control, hepatic dysfunction and renal dysfunction were investigated in 402 diabetic patients, none with evidence of cancer. Results: Median TPS level (range) was 34.6 (19–276) U/L in controls versus 40.5 (16–691) U/L in type 1 diabetes mellitus (T1DM) patients and 53 (6–1654) U/L in type 2 diabetes mellitus (T2DM) patients. TPS levels above the 95th percentile were observed in 26.1% diabetic patients and in 68.6% of these diabetic patients, raised TPS was associated with clinical complications or biochemical indicators of hepatic and/or renal dysfunction. Conclusions: The raised mean TPS levels seen in diabetic patients appear to be mainly due to the existence of hepatic or renal dysfunction. © 2006 The Canadian Society of Clinical Chemists. All rights reserved. Keywords: Tissue-polypeptide-specific antigen (TPS); Clinical complications; Diabetes mellitus; Proliferative marker Introduction Tissue-polypeptide-specific antigen (TPS) is a soluble fragment derived from the carboxy-terminal end of cytokeratin 18 (CK-18) [1]. CK-18 is a protein with a molecular weight of 45 kDa that appears to be over-expressed by rapidly growing epithelial cells. Raised CK-18 levels are associated with epithelial cell proliferation and turnover [2]. Raised TPS levels are a marker of tumour activity, not necessarily tumour mass. TPS is not specific to any particular cancer, but is a general marker for proliferating epithelial cells [2,3]. In combination with tumour markers such as CA15-3, CA125, CA19-9, CEA, and PSA, TPS determinations may offer significant advantages for cancer characterization and management [4]. However, the use of TPS for this monitoring is limited due to its non- specificity because physiological conditions such as pregnancy [5], and physiopathological situations such as hepatic or renal injury [6,7], heart transplantation [8] or diabetes [9,10], all present with elevated TPS levels. Regarding diabetes, there are no data about the prevalence of raised TPS levels or the association of raised TPS levels with clinical and/or biochemical conditions. The aim of the present study was to identify factors that may explain the raised TPS levels seen in certain diabetic patients. Materials and methods Clinical status of patients Between January 2002 and January 2004, we enrolled 402 diabetic out-patients attending the diabetes clinic of the University Hospital Complex (Santiago de Compostela, Spain), all of whom had been prescribed insulin or oral anti- Clinical Biochemistry 40 (2007) 278 – 281 ⁎ Corresponding author. Departamento de Bioquímica y Biología Molecular, Universidad de Santiago de Compostela, Campus Sur, s/n, 15782-Santiago de Compostela, Spain. Fax: +34 981 594912. E-mail address: bnmfcami@usc.es (F. Camiña). 0009-9120/$ - see front matter © 2006 The Canadian Society of Clinical Chemists. All rights reserved. doi:10.1016/j.clinbiochem.2006.11.006