Hard-wired genotype in metastatic breast cancer.

Recently, we showed by gene-expression profiling that the molecular program established in a human primary breast carcinoma is highly preserved in its distant metastases. According to the predominant model of metastasis, the capacity of a primary tumor to metastasize is acquired only rarely and late in tumorigenesis. Our findings challenge this common theory and imply that the metastatic nature of 'poor prognosis profile' breast carcinomas is an inherent feature, and not reserved to advantageous subpopulations.