Tenascin C: A defensive role in sentinel lymph nodes of melanoma patients?

Malignant melanoma accounts for nearly 80% skin-cancer-related deaths; some 20% of patients have occult nodal metastases on Sentinel Lymph Node (SLN) Biopsy, and in most cases the SLN, is the only lymph node invaded by tumor cells. To detect the presence of melanoma cells in SLNs, the reverse transcriptase-polymerase chain reaction (RT-PCR) assay is used as a highly sensitive method to identify tyrosinase mRNA. In the last years, many studies using RT-PCR have investigated the molecular pattern of gene expression in melanoma patients, to identify a molecular panel of genes useful to predict the outcome of disease. Much effort has been applied to the extracellular matrix composition and its organisation, which plays a central role in normal cellular homeostasis. It has long been recognised that the stroma surrounding a malignant tumor differs from the normal extracellular matrix, and that different expression of molecules as fibronectin, laminin and Tenascin C (TnC) has been associated with tumor progression and/or outcome of patients and . TnC is an extracellular matrix glycoprotein up-regulated under conditions of tissue remodelling in inflammatory processes, as well as during fetal and neoplastic growth ; it consists of several isoforms derived from alternative splicing and the large spliced variant is reported to regulate tumorigenesis in many tumor types. Melanoma cells constitutively synthesise and secrete TnC in vitro. In this study we investigated TnC expression in 69 SLNs obtained from 45 melanoma patients (25 males and 20 females), mean age 58.15, enrolled between 1998 and 2003. Informed consent was obtained from all patients.