Genomic profiling of viable and proliferative micrometastatic cells from early-stage breast cancer patients.
OBJECTIVE
Metastases in distant organs are the major cause of death for cancer patients, and bone marrow is a prominent homing organ for early disseminated cancer cells. However, it remains still unclear which of these cells evolve into overt metastases. We therefore established a new approach based on the analysis of viable and proliferating cancer cells by single-cell comparative genomic hybridization.


METHODS
The bone marrow of early-stage breast tumor patients (pN(0)M(0)) was screened for tumor cells by immunostaining. By applying special short-term culturing, we selected for viable and proliferative tumor cells. The short-term culturing allowed us to evaluate the proliferative potential of micrometastatic cells, which we had previously shown to represent an independent prognostic marker. We assessed genomic changes in single disseminated cancer cells by single-cell comparative genomic hybridization.


RESULTS
We found that these viable disseminated cancer cells already had a plethora of copy number changes in their genome. All of these cells showed chromosomal copy number changes with a substantial intercellular heterogeneity and differences to the matching primary tumors.


CONCLUSIONS
The established experimental strategy might pave the way for the identification of metastatic stem cells in cancer patients. Our preliminary results support the new concept that early disseminated cancer cells evolve independently from their primary tumor.
Gangnus
Rainer
R
Institut für Humangenetik, Technische Universität München, München, Germany.
Langer
Sabine
S
Breit
Elisabeth
E
Pantel
Klaus
K
Speicher
Michael R
MR
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D002874:Chromosome Mapping; D016000:Cluster Analysis; D005260:Female; D016678:Genome; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007633:Keratins / Q000378:metabolism; D007834:Lasers; D018895:Microsatellite Repeats; D008875:Middle Aged; D005810:Multigene Family; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000378:metabolism; D009693:Nucleic Acid Hybridization / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D016133:Polymerase Chain Reaction; D011379:Prognosis; D013997:Time Factors
D014408:Biomarkers, Tumor; D007633:Keratins