To explore the expression and clinical significance of complement B factor (CFB) in colorectal cancer (CRC) based on bioinformatics and cell experiments.

HPA and TIMER 2.0 databases were used to analyze the expression of CFB in CRC tissue; GEPIA database analysis of the association between CFB and MKI67 expression in CRC. Kaplan-Meier Plotter database was used to analyze the relationship between the expression level of CFB mRNA and the survival of CRC patients; Gene enrichment pathway to predict the potential biological function of CFB in CRC; IHC and Western blotting validation of CFB expression in CRC tissue. The effects of CFB on migration and invasion of CRC cells were investigated by siRNA transfection, cell scratch and Transwell assay.

The bioinformatics database showed that CFB was highly expressed in CRC tissues (P<0.001). The GEPIA database showed that CFB expression was higher in CRC tissues (P<0.05) and positively correlated with MKI67 expression (P=0.004 1). Kaplan-Meier Plotter survival analysis showed that low expression of CFB predicted poorer overall survival (P=0.015) and progression survival (P=0.048) in CRC. The enrichment results of CFB gene indicated that it might be involved in multiple progression pathways of CRC. IHC showed that the positive staining intensity of CFB in CRC tissue was higher than that in normal tissue, and TNM stageⅠand Ⅱ were weaker than Ⅲ and Ⅳ (P=0.000 1). Western blotting showed that in 10 cases of CRC and paired adjacent tissues, CFB was more expressed in cancer tissues (P=0.000 2). Cell scratch and Transwell cell results showed that CFB promoted the migration and invasion ability of RKO and SW620 cells (P<0.01).

CFB is highly expressed in CRC tissue and is associated with prognosis, while the migration and invasion ability of RKO and SW620 cells can be inhibited by low expression of CFB, indicating that it can serve as a potential prognostic marker for CRC.