Abstract
Sporadic colorectal cancer (CRC) represents an enormous problem worldwide. Large intestinal microbiota play an important role in the colorectal carcinogenesis.
The aim of the study was to investigate anti-Outer membrane protein C (anti-OmpC) antibodies, aimed at porin C, which is embedded in the outer membrane of gram-negative bacteria, in patients with colorectal adenoma (CRA), CRC and controls. The study included 22 patients with CRA (11 men, 11 women, aged 26-79, mean 65 +/- 12), 11 patients with CRC (9 men, 2 women, aged 50-83, mean 66 +/- 11) and 45 controls, blood donors (24 men, 21 women, aged 20-58, mean 38 +/- 10).
Serum anti-OmpC antibodies were investigated by means of ELISA. Values of 0-20 U/mL were considered to be negative; values > 25 U/mL were assessed as positive.
A total of 9/11 (82 %) patients with CRC had positive anti-OmpC antibodies. Anti-OmpC antibodies were negative or grey-zone in 37/45 (82 %) controls.
Serum anti-OmpC were found to be significantly higher in patients with CRC (median 42.4, interquartile range (IQR) 22.2) compared to controls (median 18.3, IQR 12.4), p < 0.001. No statistically significant difference in anti-OmpC was found between controls (median 18.3, IQR 12.4) and CRA patients (median 17.7, IQR 16.5), p=0.326.
Anti-OmpC were significantly higher in patients with CRC (median 42.4, IQR 22.2) compared to patients with CRA (median 17.7, IQR 16.5), p=0.011. Positivity of anti-OmpC antibodies was found in patients with CRC, which supports the contribution of gram-negative large intestinal microbiota to the pathogenesis of CRC.