Inclusion Criteria:

- Subjects must have a histologically confirmed diagnosis of metastatic carcinoma of
the breast; measurable disease is not required; subjects who are NED are eligible;
subjects must have had at least one prior regimen of chemotherapy, immunotherapy, or
hormonal therapy prior to entering this study; subjects may have received any number
of prior therapies for metastatic disease

- Subjects must have an ECOG performance status of 0-1

- WBC > 2000/mm^3

- Platelet count > 100,000/mm^3

- Serum creatinine =< 2.0 mg/dl

- Serum bilirubin =< 1.5 mg/dl

- SGPT < 3 times the upper limit of normal

- >= 4 weeks since chemotherapy (>= 6 weeks for nitrosoureas or mitomycin C), hormonal
therapy or radiation therapy; subjects must have recovered from all acute toxicity
associated with the prior regimen; subjects receiving concurrent hormonal treatment
or local radiation are not eligible

- Subjects must be HLA typed if not already previously done (5/10 subjects at the MTD
dose level must be HLA A2 positive)

- Subjects must not have clinical evidence of altered immune responsiveness or
autoimmune syndromes (scleroderma, systemic lupus erythematosus, etc.); subjects must
be HIV antibody negative; this treatment may be associated with increased adverse
effects for individuals with immune deficiencies, and HIV-associated symptoms
preclude accurate assessment of toxicity

- Subjects must not have undergone splenectomy

- The recombinant vaccinia vaccine should not be administered if the following apply to
either recipients or, for at least three weeks after vaccination, their close
household contacts: persons with active or a history of extensive eczema or other
eczematoid skin disorders; those with other acute, chronic or exfoliative skin
conditions (e.g., atopic dermatitis, burns, impetigo, varicella zoster, severe acne
or other open rashes or wounds) until condition resolves; pregnant or nursing women;
children under 5 years of age; and immunodeficient or immunosuppressed persons (by
disease or therapy), including HIV infection; close household contacts are those who
share housing or have close physical contact; determination of the severity of these
conditions will be made by the investigator or co-investigator

- Subjects must not have any other serious medical condition that in the opinion of the
investigator is incompatible with the protocol; subjects with active infections
requiring antibiotics are not eligible until the infection has cleared and the
antibiotics have been stopped for at least 3 days

- Subjects must have had prior vaccinia (smallpox) exposure, determined by subject
history, medical documentation, or scar characteristic of vaccinia exposure; there
must be no history of allergy or untoward reaction to prior vaccinia (smallpox)
vaccination

- Tumor tissue positive for staining with MAbs DF3 and/or DF3-P or elevated serum
CA15-3 (also known as CA27-29); note: this can be done on stored slides, but subject
will be responsible for costs if not covered by insurance

- Subjects must not have a history of seizures, encephalitis or multiple sclerosis

- Subjects must not be allergic to eggs

- Women of child-bearing potential must agree to use highly effective contraception or
abstinence prior to study entry and for at least 4 weeks after the last vaccination;
women who are breast-feeding are not eligible for this study; should a woman become
pregnant or suspect she is pregnant while participating in this study, she should
inform her treating physician immediately

- Signed informed consent

- Participants who have been previously treated with vaccinia vectors or MUC1 such as
those on protocol T98-0057 (DFPCC # 97-050) are not eligible for this study