Since its first discovery as a stem cell marker in testicular cancer [50], PODXL has been detected in several solid human malignancies, including germ cell tumours [50], astrocytoma [51], haematological cancers [52,53], and numerous epithelial malignancies including cancers of the breast, kidney, colon or rectum, prostate, pancreatic ducts, urothelial bladder, ovary, lung, thyroid, oesophagus, oral squamous cells, uterus, and stomach (Table 1). This evidence concerns the gene PODXL and breast cancer.