(p. A15) A mysterious bacterium found in up to half of all colon tumors also travels with the cancer as it spreads, researchers reported on Thursday [Nov. 23, 2017].
Whether the bacterium, called Fusobacterium nucleatum, actually plays a role in causing or spurring the growth of cancer is not known. But the new study, published in the journal Science, also shows that an antibiotic that squelches this organism slows the growth of cancer cells in mice.
Scientists are increasingly suspicious that there may be a link: another type of bacteria has been discovered in pancreatic cancer cells. In both types of cancer, most tumors host bacteria; however, only a small proportion of the cells in any single tumor are infected.
“The whole idea of bacteria in tumors is fascinating and unexpected,” said Dr. Bert Vogelstein, a colon cancer researcher at Johns Hopkins.
The colon cancer story began in 2011, when Dr. Matthew Meyerson of the Dana-Farber Cancer Institute and Dr. Robert A. Holt of Simon Fraser University in British Columbia independently reported finding Fusobacteria, which normally inhabit the mouth, in human colon cancers.
That instigated a rush to confirm. Researchers around the world reported finding Fusobacteria in colon cancers, but their work only raised more questions. The new paper, by Dr. Meyerson and his colleagues, provides some answers.
. . .
Dr. Vogelstein suggests that instead of directly causing cancer, Fusobacteria might be altering patients’ immune response — and perhaps their response to treatments that use the immune system to destroy cancers.
Alternately, perhaps the bacteria are acting more directly by secreting chemicals that spur growth in nearby cancer cells, Dr. Relman said.
“It is not unreasonable to say Fusobacterium is promoting or contributing to colon cancer,” he said.
Are Fusobacteria guilty of causing cancer? If this were a criminal case, where the jury had to be convinced beyond a reasonable doubt, Dr. Meyerson said he would have to acquit.
But if it were a civil case, judged on the preponderance of the evidence, his vote would be different: Fusobacteria are guilty.
For the full story, see:
GINA KOLATA. “Study Suggests Bacteria Have Key Role in Cancer.” The New York Times (Sat., NOV. 25, 2017): A15.
(Note: ellipsis, and bracketed date, added.)
(Note: the online version of the story has the date NOV. 23, 2017, and has the title “Why Is This Bacterium Hiding in Human Tumors?”)
The Science article, discussed in the passages quoted above, is:
Bullman, Susan, Chandra S. Pedamallu, Ewa Sicinska, Thomas E. Clancy, Xiaoyang Zhang, Diana Cai, Donna Neuberg, Katherine Huang, Fatima Guevara, Timothy Nelson, Otari Chipashvili, Timothy Hagan, Mark Walker, Aruna Ramachandran, Begoña Diosdado, Garazi Serna, Nuria Mulet, Stefania Landolfi, Santiago Ramon y Cajal, Roberta Fasani, Andrew J. Aguirre, Kimmie Ng, Elena Élez, Shuji Ogino, Josep Tabernero, Charles S. Fuchs, William C. Hahn, Paolo Nuciforo, and Matthew Meyerson. “Analysis of Fusobacterium Persistence and Antibiotic Response in Colorectal Cancer.” Science (posted online (ahead of publication) on Nov. 23, 2017).