RATIONALE: Flt3L may stimulate a person's immune system and help kill tumor cells.

PURPOSE: Phase I trial to study the effectiveness of flt3L given to patients before undergoing surgery to remove metastases from colorectal cancer.

OBJECTIVES: I. Evaluate the safety and feasibility of administering flt3 ligand to patients with hepatic metastases from colorectal cancer prior to surgical resection.

OUTLINE: Patients receive flt3 ligand subcutaneously for 14 days followed by 14 days of rest. This course of therapy may be repeated for a total of 3 courses. Leukapheresis is performed on day 15 of the last course of Flt3 ligand. Patients undergo restaging and metastasis resection. Patients are followed every 3 months for the first year, every 6 months for the second year, and yearly thereafter.

PROJECTED ACCRUAL: This study will accrue 12 patients in 1 year.

DISEASE CHARACTERISTICS: Histologically confirmed metastatic colon cancer expressing carcinoembryonic antigen (CEA) At least 50% of tumor cells must express CEA with at least moderate intensity Resectable hepatic metastases or other site of metastatic colon cancer that is resectable (e.g., lung metastases)

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: At least 6 months Hematopoietic: Absolute neutrophil count at least 1000/mm3 Absolute lymphocyte count at least 1000/mm3 Hemoglobin at least 9 mg/dL Platelet count at least 100,000/mm3 Hepatic: Bilirubin less than 2.0 mg/dL No hepatic disease Renal: Creatinine less than 2.5 mg/dL Cardiovascular: No ongoing cardiac disease No New York Heart Association class III or IV heart disease Pulmonary: No ongoing pulmonary disease such as: Asthma Chronic obstructive pulmonary disease (COPD) Active radiation- or drug-induced pneumonitis Other: Not pregnant or nursing Fertile patients must use effective contraception No history of autoimmune disease such as but not limited to: Inflammatory bowel disease Systemic lupus erythematosus Ankylosing spondylitis Scleroderma Type I diabetes Multiple sclerosis No other serious ongoing chronic or acute illness No medical or psychological impediment to study compliance No concurrent or prior second malignancy except: Nonmelanoma skin cancer Controlled superficial bladder cancer within the last 5 years No active or chronic infection including: Urinary tract infection HIV Viral hepatitis

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy Chemotherapy: No concurrent chemotherapy Endocrine therapy: No concurrent corticosteroids No concurrent hormone therapy Radiotherapy: No concurrent radiation therapy Surgery: No specified Other: No immunosuppressives such as: Azathioprine Cyclosporine A