Identification of P-cadherin in primary melanoma using a tissue microarrayer: prognostic implications in a patient cohort with long-term follow up.

Sentinel lymph node biopsy is the most accurate technique for establishing melanoma patient prognosis but is associated with morbidity and is of little value in those tumors that first metastasize to sites other than the regional nodal basin. Noninvasive methods of establishing prognosis are therefore desirable. We have used the novel technology of tissue microarray to study a cohort of 120 patients with melanoma with long-term follow-up data for the expression of P-cadherin. The tissue microarray was successfully constructed and stained. Loss of P-cadherin expression was found to be significantly correlated with outcome (log rank chi2 = 10.1336, P = 0.0015). The results suggest a fundamental role for P-cadherin in melanoma progression and identify it as a potential prognostic marker and a possible target for therapeutic manipulation.