Phase I Study of Ad5-hGCC (Human Guanylyl Cyclase C)-PADRE in Stage I/II Colon Cancer

Inclusion Criteria:

* Male and Female African American or Caucasian subjects older than 18 years of age. Race will be defined by the subject.
* Stage I or stage II (pN0) colon cancer within 3 years of surgery
* Competent immune system, defined by the ability to make a delayed type hypersensitivity (DTH) reaction to at least one of the following: candida, mumps, tetanus or trichophyton
* Adequate renal, liver, and bone marrow functions:

Serum creatinine ≤ 2.0 mg/dl, Hemoglobin ≥ 10.0 g/dl WBC (white blood cells) ≥ 3,000 /mm3, platelet count ≥ 100,000/mm3, total bilirubin ≤2.0 mg/ml, and albumin ≥ 3.0 g/dl

* Lymph node specimens available for quantification of occult metastases
* Minimum of 2 months and maximum of 36 months since surgery
* No clinical or laboratory evidence of local or systemic recurrence at entry to the study
* Expected survival of at least 6 months
* Karnofsky performance status ≥ 80 (ECOG 0 or 1)
* Willingness and ability to understand and give informed consent and follow the procedures described in the protocol

Exclusion Criteria:

* Failure to meet any of the inclusion criteria above
* Rectal cancer
* Prior chemotherapy/radiotherapy/immunotherapy/experimental medications for colon cancer
* Prior splenectomy
* Concurrent use of systemic steroids or immunosuppressive drugs (Note: topical or inhaled aerosol steroid therapies are not contraindicated for participation in the study)
* HIV-positive by ELISA, confirmed by Western blot
* Active autoimmune diseases that the Investigator considers would interfere with an immunologic response (e.g., systemic lupus erythematosus, multiple sclerosis or ankylosing spondylitis)
* Other malignancy within 5 years except curatively treated non-melanomatous skin cancer and curatively treated carcinoma in situ of the uterine cervix, or early stage (stage A or B1) prostate cancer
* Medically-proven inflammatory bowel disease
* Has at the time of enrollment, serious infection or other serious medical condition that implies a survival of less than six months
* Pregnancy or lactation (serum B-human chorionic gonadotropin test must be negative in fertile women at screening visit). Subjects will be asked to use contraception during conduct of the study.
* Past medical history of serious reaction to adenovirus vaccine
* Mental handicap
* Chronic diarrhea \>6 times per day