Clinical significance of serum claudin-1 levels in melanoma patients.

Claudins are the most important structural and functional components of tight-junction integral membrane proteins. They play roles in major cellular functions including growth and adhesion and are responsible for regulating the paracellular transport of molecules. The objective of this study was to determine the clinical significance of the serum levels of claudin-1, an oldest and important member of the claudin family, in melanoma patients. A total of 98 patients with a pathologically confirmed melanoma were enrolled into this study. Serum claudin-1 concentrations were determined by the solid-phase sandwich enzyme-linked immunosorbent assay method. Age-matched and sex-matched 43 healthy controls were included in the analysis. The median age at diagnosis was 51 years, ranging from 16 to 85 years. The majority of the patients were male (61%) and had axial localized (54%) and metastatic disease (61%). Moreover, most of the patients with metastatic disease had M1c (73%). The baseline serum claudin-1 levels of the melanoma patients were significantly lower than those of control subjects (median values 9.17 vs. 13.82 ng/ml, respectively, P<0.001). However, known clinical variables including age of the patient, sex, site of lesion, histology, lymph node involvement, stage of disease, serum lactate dehydrogenase levels, and response to chemotherapy were not found to be correlated with serum claudin-1 concentrations (P>0.05). Similarly, serum claudin-1 concentration was found to have no prognostic role in survival (P=0.524). In conclusion, serum levels of claudin-1 may have a diagnostic value in melanoma patients. However, its predictive and prognostic value has not been determined.