ONCOLOGY REPORTS 9: 51-56, 2002 Expression of CD44s and CD44 splice variants in human melanoma STELLA MARIS RANUNCOLO 1 '*, VIRGINIA LADEDA 1 '*, S US ANA GOROSTIDY 1 , ANAMORANDI 2 , MIRTA VARELA 2 , JOSÉ LASTIRI 2 , DORALORIA 1 , ROXANA DEL AGUILA 1 , ELISA BAL DE KIER JOFFE 1 , GUADALUPE PALLOTTA 2 and LYDIA PURICELLI 1 'Research Area, Institute of Oncology 'Angel H. Roffo', University of Buenos Aires; Clinical Oncology Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina Received August 31, 2001; Accepted October 8, 2001 Abstract. The ability of tumor cells to adhere and detach from extracellular matrix and endothelial cells, is a crucial step in the metastatic process and may alter the clinical prognosis of some human tumors such as melanomas. CD44, the major cell surface receptor for hyaluronate, has been implicated in cell adhesion and in tumor progression. We studied the expression of standard CD44 molecule (CD44s) and its variants v3 and v6 in 57 human primary melanoma biopsies, without previous treatment. We analyzed the association between CD44 expression and the principal clinico- pathological features, including survival. Fifty-six of 57 tumors expressed CD44s, associated to the cytoplasmic membrane. No expression of CD44v3 or CD44v6 was detected. No association between CD44s expression and prognostic factors such as tumor thickness, growth type, stage or anatomic site of the lesion was found. However, a positive correlation between CD44s expression and Clark level (Spearman, p<0.001) was found. While only 33.3% of melanomas Clark I + II showed high expression of CD44s (more than 50% of positive cells), 82.6% of melanomas Clark IV + V did so. Kaplan-Meier analysis revelead that patients whose melanomas had high expression of CD44s showed a reduced relapse free survival (RFS) rate, though without statistical significance. No difference between the level of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Correspondence to: Dr Lydia Puricelli, Area Investigation, Instituto de Oncologia 'A.H. Roffo', Universidad de Buenos Aires, Avenida San Martin 5481, Buenos Aires C1417DTB, Argentina E-mail: lydiapur®fmed.uba.ar "Contributed equally Abbreviations: CD44s, CD44 standard; CD44v, CD44 variants; RFS, relapse free survival; OS, overall survival, CMM, cutaneous malignant melanoma; ECM, extracellular matrix; MMPs, matrix metalloproteinases; CAM, cell adhesion molecule Key words: adhesion molecules, CD44, human melanoma, tumor marker CD44 expression and overall survival (OS) was found. We conclude that melanomas only expressed CD44s, and that its level was associated with Clark's stage. CD44s seems not to be useful as a tumor marker, because it does not predict either RFS or OS. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH Introduction Cutaneous malignant melanoma (CMM) constitutes a growing public health problem in the world, specially in areas that are inhabited by light-skinned populations. The incidence of melanoma is increasing faster than the incidence of cancer at any other leading site (1). Approximately 70-80% of human CMM are classified as extensive superficial type. However, primary melanoma tumors can also spread vertically (nodular malignant type), increasing the opportunity to form distant foci (2). As the prognosis of patients with malignant melanoma is determined by the development of metastatic disease, for which there is currently no effective treatment available, it is important to determine which molecular changes are related with the invasive phenotype in order to apply an early aggressive therapy. CD44 is a transmembrane glycoprotein, being one of the major cell surface receptors for hyaluronate and other extra- cellular matrix (ECM) components, such as laminin, fibro- nectin and type I and IV collagen (3-5). Recent works indicated that CD44 not only acts as a structural link from the cyto- skeleton to the ECM but it can also act as a signaling molecule (6). This polymorphic cell adhesion molecule exists as a family of proteins generated by extensive alternative splicing of up to 10 exons, and marked post-translational modification rate, such as glycosylation or glycosaminoglycan modification. All the multiple isoforms (vl-vl0) encode parts of the extracellular domain (7). The smallest CD44 isoform, lacking all variant exons, is called standard or hematopoietic form (CD44s), and is expressed almost ubiquitously compared to the CD44 variants that have much more restricted distribution. The CD44s has been implicated in several critical processes of the normal immune system development and functioning, including lymphocyte homing to mucosal lymphoid tissues, leukocyte activation, lymphopoiesis and extracellular matrix adhesion (8-10). CD44 molecules