Joe Biden hates cancer. He led the Cancer Moonshot in the Obama Administration, and, as President, he reignited it, vowing to cut death rates in half over the next 25 years. Last month, on the 60th anniversary of President Kennedy’s historic call for an actual moonshot, he vowed “to end cancer as we know it. And even cure cancers once and for all.”
Credit: Evan Vucci/AP
But, as several recent studies show, cancer is still
surprising us.
---------------
Our body has its own defenses against cancer, such as
T-cells, and great strides have been made in cancer therapies, including immunotherapies. Still, though, as first author of a new study from Tel Aviv
University, Amit Gutwillig, pointed out:
“Despite
its remarkable success, the majority of patients who receive immunotherapy will
see their tumors only shrinking in size temporarily before returning, and these
relapsed tumors will likely be resistant to immunotherapy treatment.”
One reason, it turns out, is that some cancer cells
have learned to hide – in other cancer cells.
The research found: “While the outer cells in this
cell-in-cell formation are often killed by reactive T cells, the inner cells
remain intact and disseminate into single tumor cells once T cells are no
longer present.” Sneaky little
bastards. Or, as Professor Yaron Carmi,
who heads the lab, told The
New York Times, “It was like seeing the devil.”
 |
| Cancer cell hiding. Credit: Carmi & Gutwilling/The Carmi Lab |
This is groundbreaking stuff. The authors conclude:
Overall, the ability of tumor cells to transiently enter and disseminate from each other in response to T-cell killing is a biological process that has never been described heretofore. It better explains how immunogenic tumors can survive in the host and provides a novel framework for immunotherapies
This may point to the need for new approaches. Dr. Carmi believes:
This previously unknown mechanism of tumor resistance highlights a current limitation of immunotherapy. Over the past decade, many clinical studies have used immunotherapy followed by chemotherapy – but our findings suggest that timed inhibition of relevant signaling pathways needs to occur alongside immunotherapy to prevent the tumor becoming resistant to subsequent treatments.
As interesting as the findings are, the NYT
article suggests caution: “it
remains to be seen whether it will lead to improvements in the treatment of
cancer patients.”
------------
The next set of studies are, if
anything, even more startling. It turns
out that cancer has a microbiome. And a mycobiome. Cancer tumors are filled with microbes,
particularly fungi.
Two studies published in Cell last
week document the presence of fungi in cancer tumors. The first
study looked at 35 types of cancers – and found fungi, in varying degrees,
in all of them. In many cases, they were
coexisting with bacterial colonies (the presence of bacteria in cancer tumors
had already been uncovered in the past five years).
 |
Credit: Narunsky-Haziza, et. al./Cell |
First author Lian Narunsky Haziza, of the Weizmann Institute of Science in Israel, told the NYT: “I think this is an ecosystem. It means the cancer cells are not alone.”
It's not so much there are huge amounts of fungi
present, but as STAT put it, “why are they there? And how
did they get there?” Amit Bhatt, a professor at Stanford who
was not involved with either study, told STAT; “Or maybe there
are immune cells that ate fungi and carried sequences to a tumor site. Or maybe since you have a trillion microbes
in and on you, it’s just not surprising that every now and then one makes its
way into the body.”
However they got there, Illana Livyatan, one of the
researchers, notes: “Fungi can be food for bacteria and vice
versa. They can even live within bacteria or bacteria can live within fungi.
They can do a lot of biochemistry. Any of those avenues might have an effect.”
A second study, looked specifically at fungi in gastrointestinal, lung, and
breast cancers, and its findings suggest that presence of certain kinds of fungi
are correlated with lower survival rates.
It’s not clear why. The NYT article notes: “It’s possible that some microbes don’t
just take up residence in tumors but help them grow. They may cloak the tumor
from the immune system, neutralize drugs or help tumors spread through the body.”
 |
Credit: Dohlman, et. al./Cell |
Deepak Saxena, a microbial ecologist at New York University who was not involved in either study, told Nature that “more work is needed to understand whether fungi can contribute to cancer progression by causing inflammation, for example, or if advanced tumours create a habitable environment that encourages fungal cells to take hold.”
Dr. Saxena also told
the NYT: “I was not expecting this amount of fungus in cancer. This will change the way we think about it.” Dr, Bhatt concurs, telling
Stat: “We don’t have the experiments to present a causal link
between tumor initiation or progression and fungi. But this really encourages
future research to think about designing experiments with microbiome and
mycobiome investigations in mind.”
Co-corresponding author Ravid Straussman, MD, PhD, from the Weizmann
Institute of Science, added:
“The finding that fungi are commonly present in human tumors should drive us to
better explore their potential effects and re-examine almost everything we know
about cancer through a ‘microbiome lens.”
Dr. Livyatan is optimistic about the potential applications,
telling The Times of Israel: “This
could offer a new avenue for diagnosis of cancers using a simple blood test
that detects fungi in tumors. And beyond
diagnostics, this could really shake things up in tumor research. This is one
of these eye-opening moments that makes us revisit our assumptions about
cancer, as fungi now represent a whole new consideration in analyzing tumors.”
We’ve only been scratching the surface at
understanding the presence of our microbiome/mycobiome, much less its effect on
our health, so to just now realize that we need to look at cancer through that
same “lens” just illustrates how far we most likely are from “ending cancer.”
-------------
Cancer cells hiding in other cancer cells, cancer
cells cohabiting with fungi and bacteria; who knows what else there is left to
surprise us about cancer (and other illnesses)? It’s an admirable goal that President
Biden wants to end cancer “as we know it;” the problem is, we may not really
know it all that well yet.
No comments:
Post a Comment