PFAS (per- and polyfluoroalkyl substances) have likely contaminated all major water supplies in the US. There are close to 5000 PFAS chemicals dispersed throughout the environment. Studies like these look at just a few of them.

Per- and Polyfluoroalkyl Substance (PFAS) Exposure Combined With High-Fat Diet Supports Prostate Cancer Progression, Nutrients, 30 October 2021

We observed an increase in ectopic tumor volume with PFOS exposure or an HFD [High-Fat Diet] alone; however, the fastest rate of growth was observed in mice exposed to PFOS and fed an HFD, indicating a synergistic response:

Our findings enhance understanding of how PFAS synergize with high-fat diets to contribute to prostate cancer development and establish an important basis to mitigate PFAS exposure.

Press release: PFAS exposure, high-fat diet drive prostate cells’ metabolism into pro-cancer state, Science Daily, 11 November 2021

Exposure to PFAS — a class of synthetic chemicals utilized in food wrappers, nonstick cookware and other products — reprograms the metabolism of benign and malignant human prostate cells to a more energy efficient state that enables the cells to proliferate at three times the rate of nonexposed cells, a new study in mice found.

However, consuming a high-fat diet significantly accelerated development of tumors in the PFAS-exposed mice.
…
The scientists injected an aggressive form of malignant human prostate cells into the flanks of male mice that were fed either a high-fat diet intended to mimic the typical Western diet or a control diet. Some of the mice also received oral doses of perfluorooctane sulfonate (PFOS), one of the most common forms of PFAS that has been associated with various cancers.
…
In cell culture, the scientists exposed benign prostate cells and a derivative line of aggressive malignant cells to PFOS and found that the malignant cells replicated at triple the rate of the cells in the control group.

When the researchers exposed the benign and malignant cells to another form of PFAS, perfluorobutane sulfonic acid, the malignant cells’ viability was five times greater than the cells in the control group.

Studies have associated PFBS exposure — which can occur through polluted air or polluted drinking water — with diseases of the thyroid and other organs.
…
Structurally, chemicals in the PFAS family resemble free fatty acids and bind to the same sites on serum proteins, Madak-Erdogan said.

An aside, it also says this:

Compelling evidence from human prostate cell lines and transgenic murine prostate cancer models indicates that a high-fat diet (HFD) contributes to prostate cancer progression by shifting the prostate metabolome to a pro-cancerous state.

There really is no way to avoid PFAS. They are in most people’s municipal tap water. They are in private wells and bottled spring water. They are in the air. They are on the clothes we wear, in the flesh of the animals we eat, in packaged food, and on. According to the CDC, all of us have PFAS in our bodies. The amount grows by the day because our exposure grows, and because, as “forever chemicals” they don’t break down. They accumulate.

I guess we could ring up chemical companies and ask them to stop producing PFAS and help with environmental clean-up? The EPA has been lax there.

Maybe also eat a low-fat diet? Oh, but high-fat keto is all the rage right now.