Increased exposure to bacterial antigen RpL7/L12 in early stage colorectal cancer patients.
BACKGROUND
Cancer 2010. (c) 2010 American Cancer Society. : Intestinal bacteria have long been implicated in colorectal cancer pathology, and many reports point to a close linkage between Streptococcus bovis biotype I (recently renamed Streptococcus gallolyticus) infections and tumors of the human colon. This work aims to investigate the humoral immune response to this bacterium during different stages of colorectal cancer.


METHODS
The presence of serum antibodies against S. bovis antigen RpL7/L12, previously assigned as a potential diagnostic antigen, was evaluated in Dutch (n = 209) and American (n = 112) populations using a newly developed enzyme-linked immunosorbent assay.


RESULTS
The analyses consistently showed that an immune response against this bacterial antigen was increased in polyp patients and stage I/II colorectal cancer patients as compared with asymptomatic individuals. This was not paralleled by increased antibody production to endotoxin, an intrinsic cell wall component of the majority of intestinal bacteria, which implies that the humoral immune response against RpL7/L12 is not a general phenomenon induced by the loss of colonic barrier function. Notably, increased anti-RpL7/L12 levels were not or were only mildly detected in late stage colorectal cancer patients having lymph node or distant metastasis.


CONCLUSIONS
Cancer 2010. (c) 2010 American Cancer Society. : These findings are indicative of an increased exposure to antigen RpL7/L12 during early stages of colon carcinogenesis and suggest that intestinal bacteria such as S. bovis constitute a risk factor for the progression of premalignant lesions into early stage carcinomas. Clearly, the current findings emphasize the necessity for further studies on the possible etiologic relationship between intestinal bacteria and human colorectal cancer.
Boleij
Annemarie
A
Department of Laboratory Medicine (Clinical Chemistry), Nijmegen Institute for Infection, Inflammation, and Immunity, Radboud University Center for Oncology of the Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands.
Roelofs
Rian
R
Schaeps
Renée M J
RM
Schülin
Tanja
T
Glaser
Philippe
P
Swinkels
Dorine W
DW
Kato
Ikuko
I
Tjalsma
Harold
H
D000907:Antibodies, Bacterial / Q000032:analysis*; D000942:Antigens, Bacterial / Q000032:analysis*; D015179:Colorectal Neoplasms / Q000276:immunology / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D012269:Ribosomal Proteins / Q000276:immunology*; D012307:Risk Factors; D016985:Streptococcus bovis / Q000276:immunology* / Q000302:isolation & purification
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D012269:Ribosomal Proteins; C016700:ribosomal protein L7-L12