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Disease Markers
Volume 35, Issue 6, Pages 825–832
Research Article

Altered Peptidase Activities in Thyroid Neoplasia and Hyperplasia

1Department of Nursing I, University School of Nursing, University of the Basque Country, P.O. Box 699, 48080 Bilbao, Bizkaia, Spain
2Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Bilbao, Spain
3BioCruces Research Institute, Spain
4Department of Otolaryngology, Basurto University Hospital, Bilbao, Spain
5Department of Anatomic Pathology, Cruces University Hospital, Barakaldo, Bizkaia, Spain

Received 1 July 2013; Revised 29 September 2013; Accepted 1 October 2013

Academic Editor: Dinesh Kumbhare

Copyright © 2013 Gorka Larrinaga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Papillary thyroid carcinoma (PTC), follicular thyroid adenoma (FTA), and thyroid nodular hyperplasia (TNH) are the most frequent diseases of the thyroid gland. Previous studies described the involvement of dipeptidyl-peptidase IV (DPPIV/CD26) in the development of thyroid neoplasia and proposed it as an additional tool in the diagnosis/prognosis of these diseases. However, very little is known about the involvement of other peptidases in neoplastic and hyperplastic processes of this gland. Methods. The catalytic activity of 10 peptidases in a series of 30 PTC, 10 FTA, and 14 TNH was measured fluorimetrically in tumour and nontumour adjacent tissues. Results. The activity of DPPIV/CD26 was markedly higher in PTC than in FTA, TNH, and nontumour tissues. Aspartyl aminopeptidase (AspAP), alanyl aminopeptidase (AlaAP), prolyl endopeptidase, pyroglutamyl peptidase I, and aminopeptidase B activities were significantly increased in thyroid neoplasms when compared to nontumour tissues. AspAP and AlaAP activities were also significantly higher in PTC than in FTA and TNH. Conclusions. These data suggest the involvement of DPPIV/CD26 and some cytosolic peptidases in the neoplastic development of PTC and FTA. Further studies will help to define the possible clinical usefulness of AlaAP and AspAP in the diagnosis/prognosis of thyroid neoplasms.