Safety Study of DNA Vaccine Delivered by Intradermal Electroporation to Treat Colorectal Cancer

Inclusion Criteria: * Histological confirmed AJCC stage II or III colorectal cancer * Resection of the primary tumour without evidence of remaining macroscopic disease * Allowable standard chemotherapy or radiotherapy in AJCC stage III completed minimum 2 months prior study entry * Patients recruited from vaccination with CEA66 plasmid DNA must have completed trial at 18 months if immune response is proven or proven to be non-immune responders in two consecutive immunoassays. * Age \>18 years * Karnofsky performance \>80% * Life expectancy of greater than 6 months * Normal organ and marrow function * Normal thyroid function as measured by serum T3, T4 and TSH * Normal echocardiogram regarding arrhythmias (chronic or treated atrial fibrillation allowed) * No concurrent treatment (chemotherapy or biological) may be planned during protocol treatment * Women or men of reproductive potential must agree to use adequate contraception prior to study entry and for up to 3 months after the last injection * Ability to understand and the willingness to sign an informed consent document Exclusion Criteria: * Immunotherapy or systemic corticosteroids within 8 weeks prior to entering the study * Chemotherapy or radiotherapy within 2 months prior to entering the study * Known hypersensitivity to GM-CSF * Previous splenectomy or radiation therapy of the spleen * Pregnancy or nursing * HIV seropositivity * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic intracranial disease, congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * History of severe neurological, cardiovascular, renal, hepatic, respiratory, bone marrow dysfunction, organ graft or autoimmune disease (treated or not) * Concomitant medication with an anticoagulant (acetylsalicylic acid and low-molecular weight heparin in prophylactic dose allowed) * Other malignancy, except for the following: adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, adequately treated stage I or II cancer from which the patient is currently in complete remission, or any other cancer from which the patient has been disease-free for 5 years * Cardiac demand pacemakers or surgically implanted defibrillators. * Patients that has any metal implants in the area of the injection, (e.g. shoulder implant in the upper arm or shoulder girdle)