Intratumoral microbiome signatures in a North Central Indian colorectal cancer cohort: identification of novel prognostic biomarkers and functional pathways.

Leptotrichia buccalis was significantly enriched in tumor tissue and showed significant correlation with mortality risk in early-onset colorectal cancer patients.

• L. buccalis is classified as an oral pathobiont found to be enriched intratumoral
• Identified through 16S rRNA amplicon sequencing of 50 matched tumor and adjacent normal tissue samples
• Statistical analysis conducted using DESeq2 and LEfSe methods
• Correlation with mortality risk was among the primary findings highlighted

Filifactor alocis, an oral pathobiont, was enriched in tumor tissue and correlated with mortality risk in the North Central Indian CRC cohort.

• F. alocis is an oral pathobiont identified as intratumoral enrichment
• Detected in 50 matched tumor and adjacent normal tissue samples via 16S rRNA amplicon sequencing
• Identified using DESeq2 and LEfSe analysis
• Correlation with mortality risk was a key finding alongside L. buccalis

Caldilinea aerophila was detected for the first time in human tumor tissue and was strongly associated with advanced TNM stages in the North Central Indian population.

• Association with advanced TNM stages was statistically significant (p = 0.01)
• C. aerophila showed 83% specificity for advanced TNM stage
• This represents the first reported detection of C. aerophila in human tumor tissue
• Detection was made using 16S rRNA amplicon sequencing of colorectal tumor samples from North Central India

LEfSe analysis identified overrepresentation of Actinomycetales in the intratumoral microbiome of CRC patients.

• Actinomycetales were identified as a discriminant taxon using Linear Discriminant Analysis Effect Size (LEfSe)
• Analysis was performed on 50 matched tumor and adjacent normal tissue samples
• This finding was among the key taxonomic signatures identified in the North Central Indian CRC cohort

KEGG pathway analysis revealed enrichment of MAPK signaling, styrene degradation, and aminobenzoate degradation pathways in intratumoral microbiomes.

• Functional pathway prediction was conducted using PICRUSt2 with KEGG pathway annotation
• MAPK signaling pathway enrichment suggests potential immune and oncogenic signaling involvement
• Styrene and aminobenzoate degradation pathways were identified as enriched functional pathways
• Analysis was based on 16S rRNA amplicon sequencing data from 50 matched tumor and adjacent normal tissue pairs

Lactobacillus plantarum was depleted in tumor tissue compared to adjacent normal tissue in CRC patients.

• Depletion of L. plantarum was identified through comparative analysis of matched tumor and adjacent normal tissue samples
• The depletion alongside presence of dietary-linked microbes suggests microbial modulation by lifestyle factors
• Identified using 16S rRNA amplicon sequencing and DESeq2 differential abundance analysis
• Study included 50 matched tumor and adjacent normal tissue samples from early-onset CRC patients

This study used a comparative observational design with 50 matched tumor and adjacent normal tissue samples from early-onset CRC patients in North Central India.

• Tissue samples were matched tumor and adjacent normal tissue obtained from the same patient
• 16S rRNA amplicon sequencing was the primary analytical method
• Taxonomic analysis was conducted using DESeq2 and LEfSe
• Functional analysis was performed using KEGG pathway prediction via PICRUSt2
• The study focused on early-onset colorectal cancer (EOCRC) in a North Central Indian population, described as a previously uncharacterized cohort globally