The Microbiome: Another Reason That the Moon Shots May Miss      May 20, 2013

By Leonard Zwelling

Pollan published a fascinating article in the NY Times Magazine on Sunday, May
19 (link below). All cancer care personnel should read it for it describes the
actual world in which we live, not the one imagined by the genomicists
searching the solar system of normal and malignant cell DNA for new drug
targets. Believe it or not, it was a world that I became aware of four years
ago on Capitol Hill.

to his being named NIH Director, Francis Collins took a call from a member of
the staff of the US Senate Health, Education, Labor and Pensions Committee in
which I was privileged to participate. He was asked about his top priorities
should he get the job he was so transparently seeking. One was understanding
the microbiome, a term I had never heard before.

microbiome is the world of bacteria swirling around, on and in each and every
human being. The number of cells in the microbiome of any person exceeds by an
order of magnitude the number of normal human cells in the person’s body. It is
becoming more apparent as research progresses, that the make up of each
individual’s microbiome is different, influenced by his or her geographic
locale among other factors. The microbiome is potentially of great importance
to each person’s health. Furthermore, the microbiome for any person can only be
identified through DNA gene sequencing from samples obtained from the
respiratory tract, GI tract and skin of a person. Many of the bugs are not
readily cultured in a laboratory.

this means is that along with the intrinsic genetic make-up of any person, the
tumor microenvironment and the real-world environmental factors imposing their
will on a potential inchoate cancer victim, the manner in which the normal
cells of that tumor patient-in-waiting and his or her populating flora interact
can contribute to whether or not that individual gets a cancer diagnosis. It
also means that sequencing of any explanted or biopsied human cancer might miss
a critical contributor to the etiology of the disease as does ignoring the
contribution to cancer of host factors like the immune system and the

again I return to humility as the only reasonable approach to the cancer
problem for its origins have components that we have never even dreamed of that
may make sequencing of the resultant tumor found in the clinic pale by
comparison in importance.

the article and see what you think, but the use of antibiotics, the prevalence
of processed food, the lack of available vegetables and even the increased
reliance on Caesarian section at birth may all be contributing to the
alterations in cancer rates we are seeing in the country due to their effects
on the microbiome.

importantly, it may be time to take a big step back and create an integrated
approach to our quest to understand cancer. Or, as my attending physicians and
fellow house officers said when I was a Duke intern, especially after midnight and my fifth admission: “I know life is tough, but
what did the Gram stain show?”            

Leonard Zwelling