Cladosporium sp. was more commonly found in early-onset CRC, while Pseudomonas luteola, Ralstonia sp., Moraxella osloensis occurred more often in late-onset CRC
The microbiome (MB) of patients with colorectal cancer (CRC) varies between those diagnosed with early- or late-onset disease, according to a study presented at the annual meeting of the American Society of Clinical Oncology, held from June 2 to 6 in Chicago.
Benjamin Adam Weinberg, M.D., from the Georgetown University Lombardi Comprehensive Cancer Center in Washington, D.C., and colleagues compared the intratumoral MB in patients with CRC diagnosed before age 45 years (early-onset CRC [EOCRC]) and after age 65 years (late-onset CRC [LOCRC]) in a prospective/retrospective study. DNA was extracted from tumors, and the analysis was performed with 16S ribosomal gene sequencing. The frequency of Fusobacterium nucleatum (F. nuc) and other bacterial and fungal DNA was compared in tumors from 36 EOCRC and 27 LOCRC patients.
The researchers detected 917 unique bacterial and fungal species. F. nuc was detected in 30.6 and 29.6 percent of EOCRC and LOCRC patients, respectively. EOCRC more commonly had Cladosporium sp. (30.6 versus 11 percent), while LOCRC more often had Pseudomonas luteola (2.8 versus 22.2 percent), Ralstonia sp. (22.2 versus 48.1 percent), and Moraxella osloensis (19.4 versus 44.4 percent). LOCRC patients exclusively had Clostridium perfringens (11.1 percent), Escherichia coli (11.1 percent), Leptotrichia hofstadii (11.1 percent), Mycosphaerella sp. (11.1 percent), Neodevriesia modesta (11.1 percent), Penicillium sp. (11.1 percent), and Leptosphaeria sp. (11.1 percent). No significant difference was seen in median MB diversity for EOCRC versus LOCRC patients (43 versus 45 organisms per patient).
“Because we have tumor genetic data and diet questionnaire results from many of our patients, we hope to explore more relationships and other aspects of how the microbiome impacts colorectal cancer progression in the future,” Weinberg said in a statement.