Decreased levels of aromatic microbial metabolites as a reflection of microbiota dysfunction in cancer patients

Introduction

There is growing evidence that cancer patients have altered metabolism due to disruption of the microbiome. Serum concentrations of aromatic microbial metabolites may reflect microbiota dysfunction.

Aim

The aim of this study was to evaluate the serum concentrations of aromatic microbial metabolites in patients undergoing treatment for malignant oncological diseases.

Methods

Two cohorts of patients were studied: patients with pancreatic cancer before surgery (n=64) and children with various malignant oncological diseases (leukemia, lymphoma, nephroblastoma, ependymoma, etc.) (n=40). The study used two comparison groups: healthy donors (n=18) and practically healthy children referred for preventive examination (n=18). Aromatic microbial metabolites such as phenyllactic acid, hydroxyphenyllactic acid and hydroxyphenylacetic acid were identified by GC-MS.

Results

The concentration of metabolites in the serum of patients with cancer in both studies is statistically significantly lower than that of healthy subjects. The sum of concentrations of the aromatic microbial metabolites was 1.9 (1.5; 2.2) µmol/L in healthy donors and 1.4 (0.9; 2.0) µmol/L in pancreatic cancer patients before surgery (p-value<0.001). The sum of concentrations of the aromatic microbial metabolites in children was 2.2 (1.5; 2.6) µmol/L in the control group vs 1.5 (1.1; 1.8) µmol/L in the cancer group (p-value=0.001).

Conclusions

Our study reveals the profound metabolic dysfunction of microbiota in cancer, as serum aromatic microbial metabolites were significantly different in patients compared to healthy subjects. It is promising to study the relationship between metabolic profiles and gut microbiota composition for a deep understanding of cancer pathogenesis.