The combination of a fixed dose of doxorubicin 20 mg m−2 × 3 days with escalating doses of ifosfamide (1.2–2.75 g m−2 day−1 × 5 days) with G-CSF support in a phase I study focusing in stage IV chemotherapy-naïve breast cancer has yielded the feasibility of a quite high dose of ifosfamide 12.5 g m−2 (total) with an RR of 83% of which 33% were CRs (Bitran et al, 1995). This evidence concerns the gene CSF3 and breast cancer.