Diagnostic accuracy of Fusobacterium nucleatum IgA and IgG ELISA test in colorectal cancer

Abstract

The colorectal cancer is a serious health problem. The diagnosis of the disease mostly relies on an invasive procedure. A non-invasive diagnostic test such as an immunoassay, may facilitate diagnosis of colorectal cancer. The purpose of the study was to evaluate the use of antibodies against Fusobacterium nucleatum in the diagnosis of colorectal cancer (CRC). Totally 78 patients in three groups were included in the study. F. nucleatum in the tissues was detected using quantitative polymerase chain reaction assay. F. nucleatum IgA and IgG were measured using enzyme linked immunosorbent assay. F. nucleatum was detected in 86.7% and 73.1% cases of CRC and precancerous-benign colon disease (P-BCD), respectively. The OD values from F. nucleatum IgA and IgG ELISA tests were higher in CRC group compared with healthy individuals. The sensitivity of IgA ELISA test varied between 31.8 and 95.5% depending on the chosen cut-off values. The positivity rate of antibodies in patients with high amount of F. nucleatum in tissue was significantly greater than in the negative group. The F. nucleatum IgA and IgG antibodies in CRC were higher than the ones in healthy controls but the discriminative ability of the ELISA test was not adequate to be considered as a diagnostic tool.

Figure 1

Log abundance of F. nucleatum DNA in tissues (15 CRC and 26 P-BCD patients). (A) CRC patients (B) P-BCD patients.

Figure 2

Comparison of OD values from F. nucleatum IgA and IgG ELISA in sera of CRC (n = 22), P-BRC (n = 35) and HC (n = 21) groups. Symbols indicated individual OD value; horizontal lines indicated mean values ± SD. (A) F. nucleatum IgA. (B) F. nucleatum IgG.

Figure 3

ROC curve for F. nucleatum IgA and IgG ELISA tests using serum from colorectal cancer patients and healthy controls. The reference tests were colonoscopic examination and pathological evaluation of biopsy material. IgA AUC = 0.6185, IgG AUC = 0.6481.