ORIGINAL ARTICLE Immunohistochemical localization of the NM23 protein in salivary gland neoplasms with distinct biological behavior Kelen Christine do Nascimento & Paulo Rogério de Faria & Luciano Lauria Dib & Maria Cássia Ferreira de Aguiar & Sérgio Vitorino Cardoso & Jucheng Chen & Adriano Mota Loyola Received: 27 February 2006 / Accepted: 20 July 2006 / Published online: 8 November 2006 # Springer-Verlag 2006 Abstract The NM23 protein was shown to be associated with metastasis suppression in human malignancies with various tissue origins. However, its association with the metastatic phenotype of salivary gland neoplasms (SGN) remains unknown. To evaluate the role of NM23 in SGN, the expression patterns of NM23 in the following were compared: benign (pleomorphic adenoma) vs malignant (adenoid cystic carcinoma and mucoepidermoid carcinoma) SGN, and primary malignancies with/without evidence of metastasis vs their metastatic implants (MI). The lesions were studied immunohistochemically. NM23 protein was found in the cytoplasm of 75% of benign SGN, 73.3% of primary SGN malignancies with no evidence of metastasis, 86.6% of primary SGN malignancies with evidence of metastasis, and 60% of MI. There was no statistically significant difference in the frequency of NM23-positive cells between benign and primary malignant tumors (p = 0.79), nor between primary malignancies with/without evidence of metastasis and MI (p =0.51). However, nuclear NM23 protein was restricted to primary SGN malignancies with evidence of metastasis and MI. The presence of nuclear NM23 protein may be a good marker for predicting the metastatic potential of SGN malignancies. Keywords NM23 . Salivary gland tumors . Metastasis . Prognosis . Biological behavior Introduction Metastasis is the most dreadful biological hallmark of malignant tumors and the primary cause of death in cancer patients. Salivary gland malignancies are slow-growing tumors, which eventually will develop metastasis if left untreated. However, the timing of metastasis of these malignancies varies from patient to patient. It is important to determine the metastatic potential of these tumors at the time of diagnosis because of the nature of these slow- growing tumors. Histologic grading was considered a useful parameter to predict the metastatic potential of malignancies [4, 7, 10]. However, current parameters may Virchows Arch (2006) 449:660–666 DOI 10.1007/s00428-006-0280-8 The experimental analyses of this work were performed at the Oral Pathology Laboratory of the Federal University of Uberlândia, Brazil. K. C. do Nascimento : P. R. de Faria : S. V. Cardoso : A. M. Loyola Oral Pathology, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil K. C. do Nascimento : P. R. de Faria Pathology, School of Medicine, Federal University of Triângulo Mineiro, Uberaba, Brazil L. L. Dib Stomatology, School of Dentistry, Paulista University, São Paulo, Brazil M. C. Ferreira de Aguiar Oral Pathology, School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil J. Chen Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA A. M. Loyola (*) Oral Pathology, School of Dentistry, Federal University of Uberlândia, Av. Pará, 1720 (2N/HC), CEP-38405-900 Uberlândia, Minas Gerais, Brazil e-mail: adrianol@hc.ufu.br