In a breast cancer xenograft model, injection of TRAIL-expressing CD34+ cells, CD34-TRAIL(+) cells, did not lead to tumor growth inhibition; however, lungs in the tumor-bearing mice were completely free of metastases at 12 days after the last injection of CD34-TRAIL(+) cells, whereas metastases were present in all control mouse lungs [25]. Here, CD34 is linked to breast carcinoma.