Fresh frozen tissue is needed for the genomics analysis, thus a biopsy will be required to participate in this trial. The genomic analysis will determine if the tumor is Src-active or Src-inactive and responses to dasatinib compared. In stage I, 40 patients will be treated without prior knowledge of their tumoral Src-activity. If all stage I responses are observed in the Src-active patients, the second stage will only accrue that cohort. If all responses are observed in the Src-inactive cohort, the activity of dasatinib and genomic determination of dasatinib response will be re-evaluated. Otherwise, if during Stage I, responses are observed in both cohorts, they will be accrued separately and evaluated in a two-stage manner.