Inclusion Criteria

Patients must have regionally confined histologically or cytologically proven
adenocarcinoma of the pancreas or Ampulla of Vater. Tumors must overexpress HER2 as
demonstrated by greater than or equal to 2+ immunohistochemical staining of the biopsy
specimen.

Patients must sign an informed consent.

Patients must have an ECOG performance status of less than or equal to 2.

Patients should have a serum creatinine less than 1.5 mg/dl or creatinine clearance
greater than 60 ml/hr; SGOT and SGPT less than 4 times the upper limit of normal.

Patients must have an ANC greater than 2000/mm(3) and platelets greater than
100,000/mm(3).

Patients must be at least 18 years of age.

Patients of all racial and gender groups will be included.

Patients must not have received any prior gemcitabine, radiotherapy, or Herceptin therapy
for pancreatic cancer.

Patients cannot receive concurrent hormonal or immunotherapy treatment for pancreatic
cancer.

Patients cannot receive any anti-tumor therapy within 30 days of protocol eligibility and
must have recovered from any prior treatment related toxicity.

Patients must not have evidence of distant metastases (e.g., peritoneal, carcinomatosis,
liver metastases).

No concurrent second malignancy other than non-melanoma skin cancer or cervical carcinoma
in situ.

Must not have medical conditions that preclude undergoing surgery or receiving therapy or
follow up, or have psychiatric disease which would prevent adequate informed consent or
render receiving this therapy unsafe.

No patients with an LV ejection fraction less than the lower limit of normal as determined
at the Clinical Center, NIH.

Women must not be pregnant or nursing due to the unknown effects of this therapy on the
unborn or nursing child.

Must not have received prior abdominal or pelvic radiation.

Must not have recent myocardial infarction (less than 6 months prior), unstable angina, or
congestive heart failure (NYHA class III or IV).

Must not have active diseases which make the patient more susceptible to infection,
including but not limited to AIDS, hepatitis, history of autoimmune disorders, because the
experimental treatment being evaluated in this protocol may be unsafe in the absence of an
intact immune system.