Cancer Case Rates Are Rising Across Generations and a SpaceX Private Spacewalk is Delayed

Scientists Sound Alarms on New Surge in Cancers and a Private Spacewalk is Pushed Back

By Rachel Feltman, Kelso Harper & Fonda Mwangi

Rachel Feltman: Happy Monday, listeners. Let’s kick off the first full week of August by catching up on some science news. For Scientific American’s Science Quickly, I’m Rachel Feltman.

Last Wednesday, researchers with the American Cancer Society published a study suggesting that for a number of cancers, case rates are rising from one generation to the next. They found that, in eight of 34 cancers studied, incidence rates increased with each five-year interval they looked at from 1920 to 1990. In other words, the cohort born in 1965 had higher rates than the cohort born in 1960, but lower rates than the 1970 cohort, and so on. In nine of the other cancers, while rates had declined for some time, they began to rise again in younger cohorts. The researchers emphasized that they do not yet have a conclusive explanation for the trend. While headlines often point to sedentary lifestyles and higher weights as a leading culprit, particularly for the recent surge in colorectal cancers in young people, some experts have sounded the alarm to say that these factors alone cannot explain the spike.

But we did get some good news on that front. Last Monday, the Food and Drug Administration approved a new blood test for colorectal cancer. Guardant Health’s test, called Shield, was previously available as a diagnostic tool for doctors, with its out-of-pocket price tag running almost $900. Shield doesn’t replace colonoscopies, which are crucial for spotting—and even removing—polyps that can lead to colon cancer, as well as detecting cancer itself. Research suggests the non-invasive blood test is 83% effective in catching colorectal cancer, but it works best in later stages of the disease. Still, because colonoscopies are notoriously time consuming on account of the need for bowel prep—which is often a bit unpleasant—the hope is that this blood test will cover some of the gaps in screening.

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Another recent cancer study highlighted the ever-more-apparent importance of a good microbiome. Scientists found that certain mouth bacteria seem to provide some benefit to people who have head and neck cancers, leading to better outcomes. The researchers also found that the type of bacteria in question, a common mouth resident called Fusobacterium, could outright kill some cancer cells in a petri dish setting.

In completely different health news, let’s turn to cat poop. Most people have probably heard of Toxoplasma gondii, the parasitic protozoan that causes toxoplasmosis. The parasite reproduces in the intestinal tracts of cats and infects other mammals through contact with their fecal matter. Humans can also get it from eating raw or undercooked meat. The parasite is infamous for causing infected rodents to lose their fear of cats, and for raising the risk of miscarriage in pregnant people. Last week researchers published a new study suggesting the parasite could be hijacked for positive purposes. In a nutshell, the scientists harnessed the microbe’s ability to cross the blood-brain barrier, which is notoriously tricky when it comes to delivering medication. The research is still very much in its early stages, but it looks like Toxoplasma gondii could potentially be engineered to deliver therapeutic proteins to the brain. The scientists had some success using rodent models.

Now let’s flap on over to bird flu. Listen, there’s a lot of health stuff this week! I don’t know what to tell you, that’s just the news.

Last week the Centers for Disease Control and Prevention announced a $5 million initiative to inoculate farm workers against the seasonal flu. While this vaccine doesn’t target H5N1, one of the viruses that causes bird flu, it does lower the risk of catching the flu strains that are prevalent among humans. The idea is to minimize the risk of people getting a one-two punch of flu infections and carrying around the H5N1 bird flu at the same time as a more common human flu strain. When viruses cohabitate inside a human host, they get the chance to swap genetic material. That could lead to a new strain of bird flu that’s able to hop from one person to another. Only around half of the U.S. population tends to get the seasonal flu jab, so this kind of intervention really could make a difference. Still, some folks are arguing that the U.S. should also be vaccinating farm workers against H5N1 itself, like Finland’s government reportedly plans to do. But CDC officials say they’re still weighing the pros and cons.

Okay, that’s enough healthy stuff for us. Let’s enjoy a little junk food.

SpaceX is set to send billionaire entrepreneur Jared Isaacman on the first-ever private spacewalk—but not quite as set as either had hoped. Funded by Isaacman, the Polaris Dawn mission was originally slated to launch on SpaceX’s Crew Dragon spacecraft in 2022, and the company had recently said liftoff could happen as soon as last Wednesday. During a July 26 press conference, SpaceX pushed the launch to sometime in mid-to-late August. Hopefully everyone involved is diving into a pool of money Scrooge McDuck-style to feel better about it.

Finally, we’re used to hearing about the discovery of new planets, the discovery of new species, etc. But what about new—wood? Scientists say they’ve found just that. So generally when we talk about wood types, we draw the line between hardwood and softwood. This isn’t necessarily a reference to the wood’s actual density. Hardwoods generally come from trees that have flowers and seasonal changes in their leaves. Softwoods generally come from conifers.

In a new study, scientists took a nanoscale look at the two surviving species of the Liriodendron genus, the Tulip Tree and the Chinese Tulip Tree, and found wood that didn’t fit the mold. This “midwood” structure could help explain why the trees grow so quickly and are so good at capturing carbon. Understanding that mechanism might help scientists select the best trees for carbon sequestration—and perhaps even engineer plants better suited for the job.

That’s all for this week’s news roundup. We’ll be back on Wednesday with a slightly bigger bite of science news for you to chew on. And don’t forget to tune in on Friday for the last installment in our ongoing Fascination miniseries all about the wildest kinds of archaeology research.

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Science Quickly is produced by me, Rachel Feltman, along with Fonda Mwangi, Kelso Harper, Madison Goldberg and Jeff DelViscio. Shayna Posses and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.

For Scientific American, this is Rachel Feltman. Have a great week!