This is an open -label randomized phase II study of dose-dense Fluorouracil/Epirubicin/Cyclophosphamide (FEC) administered with Epirubicin of 75mg/m2 (FEC75) and Epirubicin 90mg/m2 (FEC90) in untreated patients with early breast cancer.

Arm A: the FEC75 regimen will be given at the following doses:

Fluorouracil 500mg/m2 by i.v. bolus or infusion. Epirubicin 75mg/m2 by 30 minutes i.v infusion and Cyclophosphamide 500mg/m2 by i.v bolus or infusion. All three drugs will be administered intravenously on Day 1 of each 14-day cycles.

Arm B: the FEC90 regimen will be given at the following doses:

Fluorouracil 500mg/m2 by i.v. bolus or infusion.Epirubicin 90mg/m2 by 30 minutes i.v infusion and Cyclophosphamide 500mg/m2 by i.v bolus or infusion.

All three drugs will be administered intravenously on Day 1 of each 14-day cycles.

Pegfilgrastim fixed dose of 6mg as a single subcutaneous injection will be given in both arms on Day 2 of each cycle.

Six cycles of adjuvant chemotherapy will be administered in both arms (A + B)

Inclusion Criteria:

• patients with histological diagnosis of invasive breast cancer
• Patients with early stage I, II,III breast cancer amendable for complete surgical resection.
• Patients with any nodal status
• Patients with ER and PR -negative tumors. In case of axillary involvement:any hormonal receptors status.
• perfomance Status 0-1 on the ECOG Scale
• patients indicated for adjuvant chemotherapy
• No previous chemotherapy or radiotherapy
• Patients have to be randomized within 8 weeks after surgery. Its recommended that patients will start chemotherapy within 1 month after surgical treatment.

Exclusion Criteria:

• active infection
• pregnancy/breast feeding
• serious concomitant systemic disorders incompatible with the study
• Second primary malignancy (expect in situ carcinoma of the cervix or adequately treated basal cell carcinoma of the skin)
• Use of any other investigational agent within 4 weeks before enrollment into the study
• Cocurrent administration of radiation therapy, chemotherapy, hormonal therapy or immunotherapy