It is proposed that cancer cells express SATB1, and that SATB1 acts as a determinant for the acquisition of metastatic activity by controlling expression of a specific set of genes that promote metastatic activity. In order for cancer cells to gain the ability to metastasize, SATB1 re-organizes or re-packages genomic sequences in a specific manner to allow a switch in the pattern of gene expression. SATB1 expression was found restricted mainly to aggressive cancer cells where it may regulate the genetic and epigenetic changes that program the steps involved in the metastatic process. The present invention describes reagents and tools to detect the SATB1 protein for use in diagnosis and prognosis of aggressive cancers and therapeutics to inhibit SATB1 protein to deplete its expression in metastatic and aggressive cancers.