Circulating Tyrosinase and MART-1 mRNA does not Independently Predict Relapse or Survival in Patients with AJCC Stage I–II Melanoma

Abstract

The detection of melanoma cells in peripheral blood has been proposed to select patients with a high risk of relapse. In this study, tyrosinase and melanoma antigen recognized by T cells 1 (MART-1) mRNA expression was evaluated in serial samples obtained before definitive surgery and during follow-up in patients with American Joint Committee on Cancer stage I-II melanoma. Serial samples (n=2,262) were collected from 236 patients from 1997 to 2002. Analyses of the RNA samples were performed with a calibrated reverse transcriptase-PCR assay. Gender, age, primary tumor site, ulceration, thickness, Clark level, and histological subtype were analyzed together with tyrosinase and MART-1 mRNA treated as updated covariates in a Cox proportional-hazard model. After a median follow-up time of 66 months, 42 out of 236 patients (18%) had relapsed. The following variables were significantly associated with relapse-free survival in the univariate analyses: tyrosinase, MART-1, gender, ulceration, thickness, Clark level, and histological subtype. Entering these covariates into a multivariate Cox analysis resulted in thickness as the single independent prognostic factor (P<0.0001), whereas MART-1 (P=0.07) approached significance at the 5% significance level. The serial measurements of tyrosinase and MART-1 mRNA in peripheral blood of stage I-II melanoma patients cannot be demonstrated to have independent prognostic impact on relapse-free survival.