Immunomagnetic enrichment, genomic characterization, and prognostic impact of circulating melanoma cells.
OBJECTIVE
The finding of melanoma cells in the peripheral blood, thus far mainly inferred from the PCR-based demonstration of tyrosinase mRNA, has been associated with metastatic melanoma. Neither the malignant nature nor the prognostic significance of circulating cells could be established. To address this question, we analyzed immunomagnetically isolated circulating melanoma cells for chromosomal aberrations and performed a clinical follow-up study of the enrolled patients.


METHODS
In a prospective study, blood samples were taken from 164 melanoma patients and 50 donors without malignant disease. Circulating melanoma cells were enriched by immunomagnetic cell sorting using a murine monoclonal antibody against the melanoma-associated chondroitin sulfate proteoglycan. To prove the malignant origin of the positive cells and to define their chromosomal aberrations, we analyzed the genomes of 15 individually isolated cells from seven patients by single-cell comparative genomic hybridization (SCOMP).


RESULTS
Absolute and relative frequencies of circulating melanoma cells were associated with stage and with the presence or absence of detectable tumor. The detection of two or more cells correlated significantly with a reduced survival of patients with metastatic melanoma. All of the cells that were analyzed by SCOMP displayed multiple chromosomal changes and carried aberrations typical for melanoma.


CONCLUSIONS
Immunomagnetic enrichment enables isolation and genomic characterization of circulating melanoma cells. The prognostic impact on survival of metastatic patients apparently reflects the aggressiveness of an ongoing tumor spread. Direct genomic analysis of the enriched and isolated cells will help to clarify the molecular-genetic basis of the establishment of generalized melanoma.
Ulmer
Anja
A
Universitäts-Hautklinik, Eberhard-Karls-Universität, Tübingen, Germany.
Schmidt-Kittler
Oleg
O
Fischer
Jörg
J
Ellwanger
Ulf
U
Rassner
Gernot
G
Riethmüller
Gert
G
Fierlbeck
Gerhard
G
Klein
Christoph A
CA
D000911:Antibodies, Monoclonal / Q000737:chemistry; D002469:Cell Separation; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism; D002869:Chromosome Aberrations; D016000:Cluster Analysis; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D008545:Melanoma / Q000235:genetics* / Q000378:metabolism*; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000235:genetics* / Q000378:metabolism*; D013997:Time Factors
D000911:Antibodies, Monoclonal; D011508:Chondroitin Sulfate Proteoglycans; D012333:RNA, Messenger