RESEARCH FINDS MICROBES IN SOME CANCERS, NOT OTHERS

Researchers analysing data from Genomics England's 100,000 Genomes Project have identified which cancers harbour microbial communities and which do not. The study examined DNA from more than 16,000 tumours using what the team describes as a rigorous analysis pipeline designed to eliminate sources of error. Most cancers, including those affecting the brain, breast and kidneys, showed no distinguishable microbiome beyond background contamination. Tumours of the mouth, oesophagus, stomach and bowel, however, displayed clear evidence of microbial life.

The research addresses longstanding contradictions in the field regarding whether cancers contain bacteria, viruses and fungi. Earlier studies reported microbial signals in various tumour types, but subsequent findings could not be replicated in some cases, leaving the field without agreed standards for verification. The team's analysis suggests that previous detections of microbes in brain, breast and kidney cancers may have resulted from contamination during laboratory processing or sample handling. This contamination could originate from equipment or handling by scientists conducting the research.

The findings carry implications for cancer treatment and screening if microbes genuinely influence tumour behaviour. The research detected not only bacteria within the cancers that showed microbial presence, but also viruses, fungi, archaea and in some cases trichomonas, a single-celled parasitic protozoan. If microorganisms assist cancer growth, enable resistance to treatment or facilitate spread, they could become targets for new screening methods and drug development. Establishing reliable identification methods matters considerably because pursuing false signals diverts resources, funding and patient samples from more productive research directions.