Microbial DNA in blood may be an indication of cancer - research

A new study published in Nature Research stated that there are various types of cancer and its stages that may create microbial DNA signatures, which can be determined or identified in a person's blood.

This preliminary research was spearheaded by a team from the Centre for Microbiome Innovation at the University of California, San Diego. They have examined 33 different types of cancer and more than 18,000 samples of tumors to identify whether particular patterns of microbial DNA are found in cancer.

Gregory Poore, one of the lead researchers of the study entitled: Microbiome analyses of blood and tissues suggest cancer diagnostic approach, along with his team of scientists, have developed a new method of determining who has cancer and which type of cancer it is. The process is done by essentially analyzing the patterns of microbial DNA, both bacterial and viral, that is present in a person's blood.

Professor Rob Knight, PhD, director of the Center for Microbiome Innovation said that most of previous cancer research efforts have supposed that tumors are sterile environments and have not considered the multifaceted interaction and relationship that these human cancer cells may have with viruses, bacteria, and other microbes that live and thrive in our bodies. He also mentioned that the large number of microbial genes in a person's body outnumber the number of human genes, thus, these microbes provide significant clues to a person's health.

The team of researchers initially observed microbial data from The Cancer Genome Atlas which contain genomic and other information about patient tumors. From the evaluation of tumor samples and cancer types, microbial signatures and patterns that are associated with certain cancer types have emerged.

The scientists also assessed plasma from patients with different type of cancers such as lung and skin cancers, high-grade prostate cancer, and also people without cancer. This was conducted to evaluate whether the microbe results applied to real-life samples. All patients in the sampling were examined for signatory DNA codes.

The findings showed that the microbe signature only existed in cancer samples and there were no false positives in the results. Moreover, certain microbe signatures can be useful in potential differentiation among cancer types. In the research for example, prostate and lung cancer samples achieved 81 percent accuracy in terms of distinction.

Some microbial signatures and patterns that have emerged, as expected, are associated with certain types of cancers, such as human papillomavirus and cervical, head, and neck cancers; and Fusobacterium species was significantly more abundant and strongly linked to gastrointestinal cancers. Further, the team has discovered previously unidentified microbial signatures that strongly discriminate against other kinds of cancer. Colon cancer can be distinguished from other cancer types through the presence of Faecalibacterium species.

Knight said that there are still plenty of challenges that lie ahead as their team is still in the initial phase of developing their preliminary observations into an FDA-approved diagnostic test for cancer. There is also a need for further validation of their findings in a bigger, more diverse patient population which is a costly undertaking. Nonetheless, their latest study may prompt for crucial changes in the field of cancer biology according to Poore.