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Do poor-prognosis breast tumours express membrane cofactor proteins (CD46)?
Zahra Madjd1, Lindy G Durrant, Sarah E Pinder
1CRC Academic Department of Clinical Oncology, Nottingham City Hospital, Hucknall Road, Nottingham, NG5 1PB, UK.
Cancer Immunology, Immunotherapy : CII
|September 21, 2004
Summary
Breast tumors consistently express CD46 (membrane cofactor protein), a complement regulator. High CD46 levels correlate with tumor grade and recurrence, potentially compensating for lost CD55 and CD59, but poor prognosis persists.
Area of Science:
- Immunology
- Oncology
Background:
- CD46 (membrane cofactor protein) is a complement regulatory protein found on nucleated cells, protecting them from complement-mediated attack.
- Breast carcinomas consistently express CD46.
- Previous studies linked loss of CD59 and CD55 in breast cancer to poor survival.
Purpose of the Study:
- To investigate the prognostic significance of CD46 expression in breast tumors.
- To determine the correlation between CD46 levels and clinicopathological features in breast cancer.
Main Methods:
- Immunohistochemistry was used to assess CD46 expression in 510 breast tumor tissue microarrays.
- Standard immunohistochemistry methods and a rabbit polyclonal anti-CD46 antibody were employed.
- Patient data included long-term follow-up (median 82 months) for patients diagnosed between 1987 and 1992.
Main Results:
- CD46 was expressed in 99.4% of breast tumors.
- Strong CD46 immunoreactivity was observed in 27% of tumors.
- CD46 expression intensity correlated significantly with tumor grade (p < 0.05), histological type (p < 0.001), and tumor recurrence (p < 0.05).
Conclusions:
- High CD46 expression in breast tumors is associated with increased tumor grade and recurrence.
- CD46 may compensate for the loss of CD55 and CD59, but the loss of CD55/CD59 still indicates a poor prognosis.
- The findings suggest CD46's role in complement lysis protection and imply CD55/CD59 have additional immune regulatory functions.