Inclusion Criteria

Inclusion criteria:

- Histologically confirmed infiltrating primary breast cancer of > 2.0 cm in largest
clinical diameter

HER2 positive tumor (either IHC 3+ or FISH+)

- Availability of tumor tissue suitable for biological and molecular examination before
starting primary treatment

- Age >18, < 65 years

- ECOG PS 0-1

- Normal organ and marrow function as defined below:

leukocytes ³ 3000/microL

absolute neutrophil count ³ 1,500/microL

platelets ³ 100,000/microL

total bilirubin <= 1.5x ULN. In case of Gilbert's syndrome, <2 x ULN is allowed

AST (SGOT)/ALT(SGPT)<= 2.5 X institutional upper limit of normal

Alkaline phosphatase <= 2.5 x ULN

Creatinine within normal institutional limits

- Cardiac ejection fraction within the institutional range of normal as measured by
echocardiogram or MUGA scan

- Eligibility of patients receiving medications or substances known to affect, or with
the potential to affect the activity or pharmacokinetics of lapatinib will be
determined following review of their use by the Principal Investigator. A list of
medications and substances known or with the potential to interact with CYP450
isoenzymes is provided

- The effects of lapatinib on the developing human fetus at the recommended therapeutic
dose are unknown; women of child-bearing potential must agree to use adequate
contraception (hormonal or barrier method of birth control or abstinence) prior to
study entry and for the duration of study participation. Should a woman become
pregnant or suspect she is pregnant while participating in this study, she should
inform her treating physician immediately, the patient should be apprised of the
potential hazard to the fetus and potential risk for loss of the pregnancy

- Ability to understand and the willingness to sign a written informed consent document

- Ability to swallow and retain oral medication

Exclusion criteria:

- Stage IIIB, IIIC, and inflammatory breast cancer

- Stage IV breast cancer

- Contraindication to the treatment with anthracycline, paclitaxel and/or trastuzumab

- Prior treatment with chemotherapy, endocrine therapy or radiotherapy. Prior
treatment with EGFR targeting therapies

- Treatment with any other investigational agents, or with all herbal (alternative)
medicines

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to lapatinib

- Uncontrolled inter-current illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnancy or breastfeeding; (breast feeding should be discontinued to be enrolled in
the study)

- Women of childbearing potential that refusal to adopt adequate contraceptive measures

- HIV-positive patients receiving combination anti-retroviral therapy

- GI tract disease resulting in an inability to take oral medication, malabsorption
syndrome, a requirement for IV alimentation, prior surgical procedures affecting
absorption, uncontrolled inflammatory GI disease (e.g., Crohn's, ulcerative colitis)

- Concomitant requirement for medication classified as CYP3A4 inducers or inhibitors