Expression of complement regulating factors in gastric cancer cells.
OBJECTIVE
To investigate the deposition of complement components, C3d and C5b-9, and the expression of complement regulating factors (S protein, membrane cofactor protein (MCP; CD46), protectin (CD59), decay accelerating factor (DAF; CD55), and type 1 complement receptor (CR1; CD35)) in gastric cancers.


METHODS
Specimens of gastric cancer were examined by immunohistochemistry and immunoelectron microscopy.


RESULTS
Four complement regulating factors (S protein, MCP, protectin, and DAF) were expressed on gastric cancer cells, in ultrastructurally localised areas on the cell membrane. CR1 was not expressed. The staining intensity of DAF in both differentiated and undifferentiated adenocarcinomas was significantly higher than in histologically normal gastric epithelium. Furthermore, the staining intensity of DAF in gastric cancers showing a diffusely infiltrating growth pattern was higher than in gastric cancers showing an expanding growth pattern.


CONCLUSIONS
These data indicate that DAF may play a role in cancer cell infiltration and resistance in tumour cells.
Inoue
T
T
Second Department of Internal Medicine, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan.
Yamakawa
M
M
Takahashi
T
T
D000230:Adenocarcinoma / Q000378:metabolism* / Q000648:ultrastructure; D015703:Antigens, CD / Q000378:metabolism; D018958:CD55 Antigens / Q000378:metabolism; D018957:CD59 Antigens / Q000378:metabolism; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D015933:Complement C3d / Q000378:metabolism; D003169:Complement Inactivator Proteins / Q000378:metabolism*; D015938:Complement Membrane Attack Complex / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D009363:Neoplasm Proteins / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000648:ultrastructure
D015703:Antigens, CD; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; D003169:Complement Inactivator Proteins; D015938:Complement Membrane Attack Complex; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D015933:Complement C3d