Systematic Review and Meta-Analysis: Taurine and Its Association With Colorectal Carcinoma

Colorectal cancer (CRC) is one of the most common cancers. Various options are available for treatment, but prognosis is still poor in the more advanced stages. Current screening methods are not as accurate for distinguishing between benign and malignant growths, resulting in unnecessary invasive procedures. Recently a focus has been placed on identifying metabolites. Of these, taurine has frequently been detected, and this particular compound has a multifactorial role in human physiology.

We conducted a systematic review of studies up till November 2023. Searches were done in three databases- MEDLINE, CINAHL-Ebsco, and PubMed. Three independent reviewers filter titles, abstracts, and full-texts according to selection criteria. Ten studies (samples = 1714) were identified showing a differential level of taurine in CRC patient samples. Quality assessment accounted for the risk of bias of each study using the 'robvis' tool. Where meaningful comparisons could be made, meta-analyses were carried out using the 'R' program for precalculated effect sizes with 'metagen' in R. The 'meta' package was utilised for creation of forest plots.

Taurine was shown to significantly increase odds of CRC. It was also significantly associated with being a discriminator for CRC as a diagnostic metabolite. This was maintained at various stages of CRC. Taurine had increased expression in CRC patients, especially when the matrix utilised was blood. Nevertheless, there was significant heterogeneity for some outcomes.

In conclusion, these findings highlight the potential of using taurine as well as other bile acid metabolites (lithocholic and ursodeoxycholic acid) to diagnose CRC and illustrate the link with microbiome interactions. Overall increased taurine concentration are associated with significantly increased odds for CRC. There was mostly an increase in relative expression of taurine in CRC samples, excluding results from Wang et al.