Figure 1.
An overview of the method adopted in this study. CRC, colorectal cancer; ELISA, enzyme-linked immunosorbent assay; ETBF, enterotoxigenic Bacteroides fragilis.
Table 1.
Demographic and clinical characteristics of CRC cases and controls
| Characteristics | Cases (n = 39) | Controls (n = 39) | P value* |
|---|---|---|---|
| Sex | |||
| Male | 22 (56%) | 22 (56%) | |
| Female | 17 (44%) | 17 (44%) | |
| Age at initial diagnosis (years) | |||
| <50 | 11 (28%) | 10 (26%) | 0.49 |
| ≥50 | 28 (72%) | 29 (74%) | 0.43 |
| Mean age at initial diagnosis (years ± SD) | 58 ± 12 | ||
| Median age at initial diagnosis | 61 | ||
| Tumor grade | |||
| G1 (well differentiated) | 11 (28%) | ||
| G2 & G3 (moderately and poorly differentiated) | 17 (44%) | ||
| No information available | 11 (28%) | ||
| Tumor stage | |||
| T1 & T2 (early) | 8 (20%) | ||
| T3 & T4 (advanced) | 21 (54%) | ||
| No information available | 10 (26%) | ||
Figure 2.
Checkerboard titration results at 1:1,000 secondary antibody dilution: X-axis = primary antibody (pooled plasma samples) concentration; Y-axis = anti-ETBF IgG antibody level absorbance at OD450 nm. (A) 80 μg/mL coating antigen; (B) 50 μg/mL coating antigen; (C) 25 μg/mL coating antigen; (D) 10 μg/mL coating antigen; (E) 5 μg/mL coating antigen. ETBF, enterotoxigenic Bacteroides fragilis.
Figure 3.
Comparison of optical density (OD) values (nanometer) of anti-ETBF IgG and anti-ETBF IgA levels between CRC patients and healthy individuals (cases, n = 39; controls, n = 39). (A) Bacterial lysate as coating antigen; (B) culture broth as coating antigen. CRC, colorectal cancer; ETBF, enterotoxigenic Bacteroides fragilis.
Figure 4.
Comparison of the mean OD values (nanometer) of the anti-ETBF IgG and IgA antibody levels of CRC patients when grouped by (A) tumor grade and (B) tumor stage using bacterial lysate as coating antigen. CRC, colorectal cancer; ETBF, enterotoxigenic Bacteroides fragilis.
Figure 5.
Comparison of the mean OD values (nanometer) of the anti-ETBF IgG and IgA antibody levels of CRC patients when grouped by tumor grade (A) and tumor stage (B) using bacterial culture broth as coating antigen. CRC, colorectal cancer; ETBF, enterotoxigenic Bacteroides fragilis.