Migration-stimulating factor as a novel biomarker in salivary gland tumours Lateef E. Aljorani 1 , Agnes Bankfalvi 2 , Frank A. Carey 3 , Koji Harada 1 *, Go Ohe 1  , Sarah J. Jones 1 , Ian R. Ellis 1 , Seth L. Schor 1 , Ana M. Schor 1 1 Unit of Cell and Molecular Biology, Dental School, University of Dundee, Dundee, UK; 2 Institute of Pathology and Neuropathology, University Hospital of Essen, Essen, Germany; 3 Pathology Department, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK BACKGROUND: The identification of novel stratifica- tion biomarkers would benefit the clinical management of patients with salivary gland tumours. Migration- stimulating factor (MSF) is a potent stimulator of cell invasion, matrix remodelling and angiogenesis. The aim of this study was to determine whether MSF was expressed in salivary gland tumours and its potential value as a diagnostic biomarker. METHODS: Paraffin-embedded archival specimens of small salivary gland tumours were stained with an MSF- specific antibody. The specimens included 27 malignant and seven benign tumours; histologically normal salivary gland adjacent to the tumour was present in 16 speci- mens. MSF expression was assessed by consensus of 2–4 independent observers according to various indices, including ‘overall MSF grade’, ‘percentage of area stained’ and ‘intensity of the staining’. The motogenic effect of MSF on a salivary gland tumour cell line, HSG, was examined in the transmembrane assay. RESULTS: Overall MSF expression increased significantly in a step-wise fashion from normal salivary gland to benign and malignant tumours (P = 0.04–0.0001); with moder- ate ⁄ strong positive specimens representing 6%, 33% and 74% of the normal, benign and malignant specimens, respectively. MSF was heterogeneously expressed in both carcinoma and stromal cell compartments, its expression being higher in malignant than benign tumours regarding various MSF indices. In tissue culture studies, exogenous MSF stimulated the migration of HSG cells. CONCLUSIONS: These immunohistochemical and functional studies suggest that MSF expression is a potentially useful biomarker of salivary gland tumour progression. J Oral Pathol Med (2011) 40: 747–754 Keywords: benign tumours; cancer; disease progression; MSF; salivary gland tumours Introduction Salivary gland tumours (SGT) are relatively rare lesions, accounting for only 3–6% of all head and neck neoplasms. They are a morphologically and clinically diverse group which present a challenge to head and neck surgeons and pathologists, both in terms of diagnosis and clinical management. The majority of tumours arising from the minor salivary glands are malignant (1–4). The identification and validation of novel stratification and predictive biomarkers for SGT would consequently be of significant clinical utility. Migration-stimulating factor (MSF), a soluble genet- ically truncated isoform of fibronectin, is a potent oncofoetal regulatory molecule. Its 2.1-kb message is transcribed from the fibronectin gene by read-through of intron 12, followed by premature intra-intronic cleavage. As a consequence of this post-transcriptional foreshortening, MSF message is identical to the 5¢ end of fibronectin (up to and including exon III-1a), followed by a 30-bp intron-derived in-frame coding sequence and a 165-bp 3¢-UTR. The 70 kDa MSF protein is conse- quently identical to the N-terminus of fibronectin and terminates in an MSF-unique (intron-coded) 10 amino acid sequence not present in any full-length fibronectin (5, 6). Immunohistochemical studies (using antibodies raised against the MSF-specific C-terminal decamer) indicate that MSF is expressed by keratinocytes, fibroblasts and vascular endothelial cells during foetal development, but is generally not expressed in healthy adult skin. MSF is transiently re-expressed during acute wound healing (7) and persistently re-expressed by both tumour and stromal cells in a number of common human cancers, Correspondence: A. M. Schor, Unit of Cell and Molecular Biology, Dental School, University of Dundee, Dundee, UK. Tel: +44 (0) 1382 635987, Fax: +44 (0) 1382 635998, E-mail: a.m.schor@dundee.ac.uk *Present address: Department of Oral and Maxillofacial Surgery, Yamaguchi University Graduate School of Medicine, Japan   Present address: Department of Oral Surgery, Institute of Health Biosciences, University of Tokushima Graduate School, Japan Accepted for publication March 2, 2011 doi: 10.1111/j.1600-0714.2011.01044.x J Oral Pathol Med (2011) 40: 747–754 ª 2011 John Wiley & Sons A/S Æ All rights reserved wileyonlinelibrary.com/journal/jop Journal of Oral Pathology & Medicine