Loss of CD55 is associated with aggressive breast tumors.
OBJECTIVE
CD55 is a complement regulatory protein expressed by cells to protect them from bystander attack by complement. CD55 is overexpressed on some tumor cell lines, and in colorectal carcinomas, it has been shown to be an indicator of poor prognostic.


METHODS
A large set of samples (480) from patients with primary operable breast cancer followed for 4-192 months were included in the present study. The prognostic significance of CD55 was then investigated in these tumors using an anti-CD55 monoclonal antibody (RM1) that we raised against a synthetic peptide and a standard immunohistochemistry method.


RESULTS
Ninety-five percent of the breast carcinomas expressed CD55 (RM1) with intensity ranging from weak (51%) to strong (6%). High expression of CD55 was significantly associated with low-grade (grades 1 or 2; P = 0.001), lymph node negativity (P = 0.031), and good prognosis tumors (Nottingham Prognostic Index < 3.4; P < 0.001). Survival analysis showed CD55 overexpression was associated with a more favorable outcome and loss of CD55 being associated with poor survival (P = 0.001). Intensity of CD55 expression was significantly correlated (P = 0.002) with intensity of CD59 expression (as shown in a previous study) in these series of patients.


CONCLUSIONS
In conclusion, we found that loss of both CD55 and CD59 in breast carcinomas is associated with a worse prognosis.
Madjd
Zahra
Z
Cancer Research UK Academic Unit of Clinical Oncology, University of Nottingham, City Hospital, Nottingham, United Kingdom.
Durrant
Lindy G
LG
Bradley
Richard
R
Spendlove
Ian
I
Ellis
Ian O
IO
Pinder
Sarah E
SE
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018958:CD55 Antigens / Q000096:biosynthesis*; D018957:CD59 Antigens / Q000096:biosynthesis; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000737:chemistry; D011379:Prognosis; D013997:Time Factors; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D018958:CD55 Antigens; D018957:CD59 Antigens; D010455:Peptides