No, we’re not talking about human cancer; we’re talking about cancer in wild animals, and whether human activity may be causing it. Excerpt:
As humans, we know some of the factors that can cause cancer to develop in our bodies. Smoking, poor diets, pollution, chemicals used as additives in food and personal hygiene products, and even too much sun are some of the things that contribute to an increased risk of cancer.
But, are human activities also causing cancer in wild animals? Are we oncogenic — a species that causes cancer in other species?
Researchers from Arizona State University’s School of Life Sciences think so and are urgently calling for research into this topic. In a paper published online today in Nature Ecology & Evolution, Mathieu Giraudeau and Tuul Sepp, both postdoctoral researchers in the lab of ASU life sciences Professor Kevin McGraw, say that humans are changing the environment in a way that causes cancer in wild animal populations.
“We know that some viruses can cause cancer in humans by changing the environment that they live in — in their case, human cells — to make it more suitable for themselves,” said Sepp. “Basically, we are doing the same thing. We are changing the environment to be more suitable for ourselves, while these changes are having a negative impact on many species on many different levels, including the probability of developing cancer.”
How can this happen?
Sepp said: “It is already known in human studies that obesity and nutrient deficiency can cause cancer, but these issues have been mostly overlooked in wild animals. At the same time, more and more wild species 
are in contact with anthropogenic food sources. In humans, it’s also known that light at night can cause hormonal changes and lead to cancer. Wild animals living close to cities and roads face the same problem — there is no darkness anymore. For example, in birds, their hormones — the same that are linked to cancer in humans — are affected by light at night. So, the next step would be to study if it also affects their probability of developing tumors.”
OK, while the jury (hah) seems to still be out on this, let’s say that continued research does uncover increased rates of cancer in mammals and birds caused by human agriculture and nighttime lighting. If that is at some point known to be the case, I would have one question:
And therefore, what?
Are we to stop growing agricultural crops? Shut off all our streetlights, yardlights, airport runway lights, house lighting, traffic lights, and the bazillion other ways humans have chosen to illuminate the dark hours?
This strikes me as research with no real purpose. Speaking as a biologist and an outdoor enthusiast, I am certainly all in favor of taking proper care of our environment and not carelessly doing damage to populations of wildlife; but this if this is shown to be a 
problem, I can’t see how it can be solved.
Every species in the billions of years life has been on this planet has had effects on other species in their environment. Humans are unique in that we are aware of our impact and care about it. But there are limits; we have to have food crops and we are going to use artificial lighting in hours of darkness. That’s not going to change. Perhaps the work of McGraw and his team will find some reasonable ways to attenuate that effect, but we’ll never eliminate it.
