Here’s one to tell you about. I read once that “there are 32 million brain tumors in the world. In Europe, the number is between 20 and 30 million, and only around 3 to 3.5 million cases of non-Hodgkin’s lymphoma.” Nobody expected such a low number, and no one thought that it was a potential reason for future more aggressive treatment. There you go, you’re telling me that the same disease was going to go away. It’s nice to get a little confirmation that our lives do not always play out according to conventional wisdom.

I believe that an estimated three million Americans are diagnosed with brain cancer, and researchers say it may be getting worse. At first glance, the percentage isn’t big. In England, a study of 26,000 people found that in 1983, cancer of the brain seemed to be falling in rate. With the rise of brain tumors, that number rose and stayed relatively stable until 2014. Now scientists in Belgium have found that they have more new pieces of evidence indicating that a different path of brain cancer development is taking place.

What’s more, the Portuguese research suggests that many more people have been diagnosed than is usually thought.

A pastel in this picture shows the production of brain tumor cells.

In lab tests, mice with tumors expanded faster than those who weren’t. Once the tumor started dividing, it wasn’t very difficult to shut it down—just about as hard as shutting it down before a previously diagnosed tumor began dividing.

There’s no solid evidence for why this is, but researchers say there is evidence that it might be some kind of innate change, which happens automatically when we develop cells that look different from ones we’ve been exposed to for thousands of years. Without this natural reset, it may be hard to treat such a disease.

We may have a hard time solving this phenomenon because of the extensiveness of these brain tumors. Many cases can go undetected until they grow too large, and some can develop metastatic malignancies. However, studies of these tumors have detected abnormalities in the cells and created new types of tumors, such as one called those in the glioblastoma domain of brain tumor cells. That’s not a very big population of tumors—they grow slowly, but if you have it you can be very vulnerable to dangerous attacks. It’s like when we thought of marijuana in ancient Rome as marijuana; now it’s like marijuana again—or moss—and we still don’t know why.

Virtually no one knows why brain tumors develop differently, but we should all be paying close attention. They could develop tumors because something in the body alters the way our brains work, and there are many ways this can happen.