Antibody responses to flagellin C and Streptococcus gallolyticus pilus proteins in colorectal cancer

Antibodies to Streptococcus gallolyticus subspecies gallolyticus (SGG) have been associated with colorectal cancer (CRC). Because SGG may correlate with impaired gut epithelia, we assessed the association of antibodies to bacterial flagellin C (FliC), a measure potentially related to this impairment, with CRC and the CRC-specific interaction with antibodies to SGG proteins. Antibodies to FliC and SGG pilus proteins Gallo2178 and Gallo2179 were measured in two independent studies, a combined study from Nijmegen and Detroit (93 CRC cases, 74 controls) and a replication data set including 576 cases and 576 controls from the Spanish multicenter multicase-control study (MCC-Spain). Logistic regression was applied to assess whether antibodies to FliC were associated with CRC and modified the association of antibodies to SGG proteins with CRC. Antibodies to FliC were associated with those to SGG Gallo2178 among CRC cases, resulting in an interaction in the association of antibodies to Gallo2178 with CRC (p = 0.007). This association was only present among individuals with high antibody responses to FliC (OR: 2.42, 95% CI: 1.45–4.06). In conclusion, our findings suggest that colorectal tumorigenesis could be accompanied by an impaired integrity of the epithelium that could result in associated increased antibody responses to bacterial proteins.
We thank Shaynoor Dramsi and Camille Danne (Department of Microbiology, Institut Pasteur, Paris, France) for providing the purified proteins Gallo2178 and Gallo2179. This work was supported by the National Institutes of Health (grant number R01-CA93817, Ikuko Kato); The Netherlands Organization for Scientific Research (NWO 016.166.089 to A. B.); the "Accion Transversal del Cancer", approved on the Spanish Ministry Council on the 11th October 2007; the Instituto de Salud Carlos III-FEDER funds -a way to build Europe-(grants numbers PI08/1770, PI08/0533, PI08/1359, PS09/00773, PS09/01662, PS09/01286, PS09/01903, PS09/02078, PI11/00226, PI11/01403, PI11/01810, PI11/01889, PI11/02213, PI12/00150, PI12/00265, PI12/00488, PI12/00715, PI12/01270, PI14/00613, PI17/00092); the Fundacion Marques de Valdecilla (grant number API 10/09); Obra Social CAJASTUR (grant number SV-CAJASTUR-1); Recercaixa (grant number 2010ACUP 00310); Spanish Association Against Cancer (AECC) Scientific Foundation; Agencia de Gestio d'Ajuts Universitaris i de Recerca (AGAUR) -Generalitat de Catalunya (Catalonian Government) (grant numbers 2009SGR1026, 2009SGR1465 and 2017SGR723); and Junta de Castilla y Leon (grant number LE022A10-2). Sample collection and storage was partially supported by the Instituto de Salud Carlos III-FEDER (grant number RD09/0076/00036), Xarxa de Bancs de Tumors de Catalunya sponsored by Pla Director d'Oncologia de Catalunya (XBTC).