Bj. Curry et al., MART-1 is expressed less frequently on circulating melanoma cells in patients who develop distant compared with locoregional metastases, J CL ONCOL, 17(8), 1999, pp. 2562-2571
Purpose: Polymerase chain reaction (PCR) with tyrosinase and with MART-1 pe
rmits detection of small numbers of circulating melanoma cells (CMCs) in pa
tients who have undergone surgical resection of localized disease. In a pre
vious study, we showed that PCR with MART-1 had sensitivity and specificity
similar to those of PCR with tyrosinase in terms of detection of CMCs but
that PCR with MART-1 seemed to identify a different but overlapping subgrou
p of patients. In the current study we examined the utility and prognostic
significance of PCR with tyrosinase and with MART-1.
Patients and Methods: We analyzed the prognostic significance of the patter
ns of expression of tyrosinase and MART-1 in 186 patients followed sequenti
ally before and after surgical removal of American Joint Committee on Cance
r stage I, II, or III melanoma.
Results: PCR with tyrosinase and with MART-1 in the first 3 months after su
rgery identified 68.5% of 73 patients who developed recurrence in the 2-yea
r period after surgery. Approximately 35% of patients with positive tests r
emained disease-free at 5-year followup. We found that patients with dissem
inated recurrence had a significantly lower incidence of MART-1-positive CM
Cs (16%) than of tyrosinase-positive CMCs (63%). Patients with locoregional
metastases had CMCs that expressed tyrosinase and MART-1 at similar rates.
These differences in expression of the markers in patients with disseminat
ed recurrence were also associated with a much lower disease-free survival,
in those who had CMCs that were positive for tyrosinase but negative for M
ART-1. The reverse applied in those with locoregional disease.
Conclusion: These findings suggest that PCR with MART-1 and with tyrosinase
identifies subgroups of patients who develop disseminated or locally recur
rent metastases. We hypothesize that immune responses against MART-I may re
duce the establishment of disseminated metastases. (C) 1999 by American Soc
iety of Clinical Oncology.