Table 5. Mucin based therapeutic strategies for breast cancer.

Ref.	Nature of therapeutic strategy	Name of vaccine	Mucin targeted	Other immunogens	Vector	No. of patients	Vaccination schedule	Response (against mucin antigen)	Adverse effects
[108]	Vaccine	PAN VAC	MUC1	1. CEA 2. T-cell co-stimulatory molecules (B7.1, ICAM-1 and LFAA-3)†	1. Vaccini a virus (Wyeth strain) – primary immunization 2. Replication deficient avian pox virus-booster doses	25 (8 female, 17 male). 2 breast cancer.	Single dose of 1° vaccination (s.c.) followed by boosters on day 15,29,43. Then boosters q28 days till patient was on the study	1. Immune response: 4/14 patients showed production of MUC1 specific T-cells post-vaccination 2. Clinical response: 21% reduction in unidimensional sum of tumor size (according to RECIST criteria) associated with immune response to MUC1 and CEA. Ultimately CA27.29 (TM) returned to above baseline levels. This patient had improved response to post-vaccination chemotherapy ‡ for 15 months associated with marked reduction in CA27.29 levels.	Apart from injection site reaction, grade ≥2 toxicity was seen in <3% patients
[107]	Vaccine	N/A	MUC1	KLH (conjugated to MUC1) and QS-21ψ	N/A	Nine breast cancer patients with no evidence of disease (NED) at time of entry into study	5 s.c. doses of MUC1-KLH+QS-21 given at weeks 1,2,3,7 and 19	1. ↑ in IgG (mainly IgG1 and G3) in all patients post-vaccination. 7/9 patients had significant ↑ in IgM levels that bound to MCF-7 cells. In contrast, only 3/9 patients had showed a positive binding of IgG to MCF7 cells.2. 2/9 patients developed recurrence during vaccination. Since all patients were NED at start of study, tumor response was not the end point.	1. Most common: skin reaction (at injection site). 2. Other reactions: fever, myalgi as, NVD€, fatigue and headache
[109]	Vaccine	Theratrope ™ (Biomira Corp., Edmonton, Canada)	Underglycosylated, mucin associated glycoprotein STn	None (patients also received concomitant hormone therapye)	None	None (in vitro assay of mechanism underlying response to vaccine)	N/A	1. ER+STn+MUC1+ (but not ER-STn +MUC1+ or ER+STn-MUC1+) cells showed significant increase in monocyte mediated ADCC when treated with anti-STn or anti-MUC1 antibodies in presence of the aromatase inhibitor. 2. In absence of antibodies, formestan inhibited monocyte mediated ADCC	None
[110]	Vaccine	N/A	MUC1 VNTR	GM-CSF€	pUC plasmid	None (SCID mice inoculated with human PBLs)	Two i.p. inections on day 7 and day 21 after MCF-7 injection s.c.	1. Incidence of tumors in animals injected with rBCG-MVNTR4-CSF (25% on day 35, 63% on day 70) or rBCG-MVNT8-CSF (25% on day 35, 38% on day 70) was significantly lower than that in control mice (100%) e 2. Significant induction of MUC1 specific CTL response as measured by Ellispot test in mice receiving the MUC1 vaccine.	None
[112]	Gene therapy	N/A	MUC1 (DF3)		Replication deficient adenovirus (adenovirus 5)	None (cell lines: MCF7, ZR-75-1, BT-20, MDA-MB231) and athymicnude mice	N/A	1. β-galactosidase expression, driven by the DF3 promoter was noted only in the MUC1 positive cells. 2. Cells infected with adenovirus containing HSV-tka enzyme under the DF3 promoter showed significant cell death upon treatment with ganciclovir 3. Mice injected with MCF-7 cells intraperitoneally followed by Ad-DF3-tk/Ganciclovir i.p. showed significant reduction in the size of tumors and incidence of ascites.	None. However, when the adenoviruses (Ad-DF3-tk) were given i.v., no therapeutic effect was evident.
[111]	Gene therapy	N/A	MUC-1	None (cells were co-infected with retrovir uses encoding various ILs like IL-2, IL-4, IL-12, and IFN-γ)	Retrovirus (TFG-mIL-12)	None (conducted in MUC-1 transgenic mice using mouse mammary adenoca rcinoma cell line (410.4) in aBALB/c background)	N/A	1. The cells that had been modified to secrete IL-12d had significantly lower tumorigenecity (compared to cells expressing either only MUC-1 or MUC-1 + IL-2/IL-4/IFN-γ). 2. T-cell mediated cytotoxicity developed in the transgenic mice which had rejected IL-12 secreting 410.4 cells, associated with immunity to development of breast cancer (upon subsequent injection of MUC-1 expressing 410.4 cells): Potential for autologous therapy in breast cancer patients.	None
[114]	RIT*	N/A	Anti-mucin mAb (2G3) labeled with I131 MUC1	None	N/A	11		1. 3/9 patients receiving escalated doses (>50 mCi) showed a partial response (reduction in ascites). 2. Drawback: Specific uptake of the radiolabeled antibody by the tumor was seen only in 2/5 patients who were biopsied (suggests that the antitumor effect was mostly due to retention of the radioactivity within the peritoneum)	Not significant
[113]	Immunotherapy	N/A	(DF3 and its bispecific antibody DF3×H2 2)	None	N/A	None (cell lines: ZR75-1)	N/A	1. ADCP, but not ADCCb was observed with both DF3 and DF3xH22 (more with the former mAb). 2. ADCP was inhibited by ↑ by IFN-γ than GM-CSFc	N/A
[115]	Immunotoxin	BM7-PE	MUC-1 (mAb BM7)	BM7 conjugated to	N/A	None (nude rats); MT-1 and MA-11 human breast cancer cell lines	N/A	1. In vitro: IC-50 for BM7 was 4-25 ng/ml. 2. In vivo: Treatment with BM7-PE significantly ↑ symptom-free survival to 41.3 days when given from day 1 (following injection of tumor cells intracardiac) but produced no significant benefit when given 7 days after initial injection (control rats had mean symptom free survival of 25.8 days) 3. In vivo: 80μg (but not 40μg) BM7-PE prevented tumor formation in 3/5 rats (p=0.003) when administered 7 days after intratibial injection of tumor cells.	The response to BM7-PE appeared to be dependent on the express ion of MUC1 by the tumor cells.

^€Granulocyte Monocyte Colony Stimulating factor (GM-CSF)

^†Intercellular adhesion molecule-1 (ICAM-1), lymphocyte function associated-antigen 3 (LFAA-3)

^‡paclitaxel and bevacizumab,

^¶Pseudomonal exotoxin A

^ψKey hole limpet is an immunogenic protein isolated from the blood of the organism by the same name while QS-21 is obtained from the bark of Quillaja saponaria, native to South America.

^€nausea, vomiting and diarrhea

^*Radioimmunotherapy (RIT)

^aHSV-tk is an enzyme that phosphorylates and activates Ganciclovir. The drug, which is non-toxc to mammalian cells, becomes toxic when activated by HSV-tk

^bAntibody dependent cell phagocytosis (ADCP) and antibody dependent cell cytotoxicity (ADCC)

^cgranulocyte-monocyte colony stimulating factor (GM-CSF)

^dIL-12 is a potent T-cell stimulating cytokine that induces secretion of IFN-γ and TNF-α from the T-cells. It also promotes development of Th1 CD4⁺ cells (involved in cell mediated immune response) and tumor infiltrating lymphocytes

^eAromatase inhibitor Formestane

^eBacillus Calmette Guerin (BCG) bacilli transformed with a plasmid encoding the VNTR region 4 or 8 of MUC1 in frame with GM-CSF.