Immunohistochemical Mdm2 expression in minor salivary gland tumours and its relationship to p53 gene status

Mdm2 protein is a cellular regulator of p53 protein activity. Minor salivar y gland tumours were investigated for immunohistochemical expression of Mdm 2 protein and for p53 gene status. Formalin-fixed sections were submitted t o monoclonal antibody anti-Mdm2 through use of the streptavidin-biotin meth od. Nuclear immunoreactivity was scored 1 (0-25% nuclei positive), 2 (26-50 %), 3 (51-75%) and 4 (> 75%). The scores found were: PLGA = 1-4; ACC = 3 an d 4; ACA = 2 and 4; PA = 3. Genomic DNA of p53 gene exons 5-8 was examined by polymerase chain reaction and no alterations were detected. The strong i mmunohistochemical Mdm2 expression may represent an alternative mechanism t o the development of salivary gland tumours. (C) 2000 Elsevier Science Ltd. All rights reserved.