Cancer spread is increased by a high fat diet...

After reading the source paper, I find it interesting that the methods don't specify that the control and high fat diet mice were fed isocaloric diets. Under Methods > Animal Studies:

"High-fat diet experiments were performed by feeding the mice with a 60/Fat Research diet (TD.06414, Harlan) for 7 days before inoculating the mice with the tumour cells and thereafter. Normal diet was used for control groups. For doxycycline treatment, mice were treated continuously with 50 μg ml–1 of fresh doxycycline in light-protected drinking water that contained 5% sucrose. Glucose levels were measured once a week at a controlled time by using a glucometer (BAYER, ContourRnext)." nature.com/nature/journal/vaop/ncurrent/full/nature20791.html

I find it difficult to comment when that variable, that I would think would be an obvious one to control, isn't accounted for. Maybe it is mentioned elsewhere and I missed it?

I will say that I've seen papers with similar results (not the metastasis, but the increased tumor size) in human cell culture before when the typical culture media (which is very low fat) is supplemented with fats to levels typical of human blood. However, it was considered questionable that the increased size would lead to poorer outcomes (except where tumor size has an impact - such as blocking the esophagus) because the larger tumors were due to internal necrotic lesions. The overall cell proliferation was determined to be at the same rate as the controls.

I'll also comment that CD36 is present on a lot of cell types (platelets, erythrocytes, monocytes, differentiated adipocytes, skeletal muscle, mammary epithelial cells, spleen cells and some skin microdermal endothelial cells) - from Wikipedia, but accurate as far as it goes. There are more recently discovered types that are also CD36+. To my knowledge, and I don't study cancer so I may be completely off base, cancers originating in those cell types are not unusually metastatic save for the ones that pretty much circulate freely and have that advantage. I'd be curious to know if the metastatic cells for those types of cancers correlate with increased functional CD36+ on the cell membrane. Just increased expression of CD36 wouldn't necessarily mean anything.

I have so many people in my life who are dying of cancer. Everything causes cancer. Take care of yourselves, mind and body, while you're young, be mindful about what you put in your body and breathe in....In the end, even if you do absolutely everything right, it could still get you.

Very intetesting. I wonder if doxycycline's effect on intestinal flora has any influence on the result

Does it say what kind of fat, O3 vs O6 %, levels of inflation? IMH non scientific opinion, there is just to much that can have an affect that they are not looking at.