The prognostic value of a reverse transcriptase-PCR assay of sentinel lymph node biopsy for patients with cutaneous melanoma: A single-center analysis in Japan

Sentinel lymph node biopsy (SLNB) is the standard of care for staging melanoma. However, limited research has been carried out on the prognostic value of SLNB in patients with primary cutaneous melanoma in Asian countries. The objective is to evaluate the efficacy of SLNB in Japanese patients with primary cutaneous melanoma and to elucidate whether reverse transcriptase (RT)-PCR analysis of sentinel lymph nodes (SLNs) is valuable for predicting patient outcome. A total of 101 patients with primary cutaneous melanoma underwent SLNB at the Department of Dermatology, Kyushu University (Fukuoka, Japan), between May 2001 and December 2009. The removed nodes were stained with hematoxylin-eosin and with immunohistochemical stains for HMB-45, tyrosinase, MART-1, and MITF and multiple-mRNA marker (MART-1, tyrosinase, and GP-100) RT-PCR assays were conducted. The following clinicopathological variables were evaluated: age, sex, histological type, tumor site, Breslow thickness, disease-free survival (DFS), and melanoma-specific survival (MSS). Several parameters were analyzed for DFS and MSS using the Kaplan-Meier method and Cox proportional hazards model. The success rate of identifying SLNs was 98% (99 of 101 cases). Tumor-positive SLNs were significantly correlated with higher Breslow thickness, stage, tumor subtype, and tumor site. Patients with tumor-positive SLNs had a significantly shorter MSS and DFS than those with tumor-negative SLNs (P=0.0153 and 0.0004, respectively). Patients with at least two positive markers in the RT-PCR assay had a significantly shorter DFS than those with less than one marker (P=0.013). SLNB and multimarker RT-PCR analysis are useful for predicting the prognosis of patients with melanoma.