Similar to our results with MDA-MB-231 cells, loss of podocalyxin expression in 4T1 cells also impaired the metastatic potential of these cells in an experimental model of lung metastasis using immunocompetent BALB/c mice (greater than threefold reduction), as shown by manual counts of tumor nodules on the lungs (Figure 4B) and by luciferase assays of lung homogenates (Figure 4C). The gene discussed is PODXL; the disease is neoplasm.