I am principal investigator in some project that involves other research groups from other countries. When I was writing the proposal, I asked them if they would like to joint the project, and they agreed. I wrote everything, all paperwork, etc. Now, 6 months after the project has been officially started, they are not contributing in any way to the project, only attending project meetings where they talk about their universities, but nothing about the project. I am really annoyed because the situation. From my point of view they should get involved, as my group does. Before asking them directly for the last time in probably in an unpolite way if they will do their assigned part, how would you proceed here?


Question: Does scratched Teflon coated frying pans contain carcinogens which can cause cancer?
Answer: The question and link imply that if cooking with Teflon generates carcinogens that carcinogens then always lead to cancer. This is not always true. In some cases exposure to carcinogens may signal protective pathways. Oncogenesis and exposure to both genotoxic and non-genotoxic carcinogens are not always positively correlated. Cooking with Teflon influences how you cook, and it's how you cook that has the greatest effect on the levels of carcinogens in food.

Cooked food contains carcinogens in the form of reactive oxygen species. This is related more to the heat its cooked at than the type of cookware used. Carcinogen exposure in the heating of biological material is an interesting subject.

Carcinogens can be classified in 2 categories (1):


Genotoxic carcinogens (Reactive Oxygen Species/ROS)
Non-genotoxic carcinogens (PFOA is thought to be here)


Genotoxic carcinogens facilitate the formation of cancer through alterations in a cell's DNA. 

Non-genotoxic '...carcinogens have no direct interaction with DNA; they are believed to cause tumors by disrupting cellular structures and by changing the rate of either cell proliferation or of processes that increase the risk of genetic error. (1)'

The molecular mechanism most often thought of for cancer formation is genotoxic oncogenesis, damage to DNA. Here, genotoxic oncogenesis often involves a reactive oxygen species (ROS). ROS may generate free radicals which, when reacting with other molecules, generate more free radicals. Another example of a reaction involving free radicals is a fire. Human cells contain genes for antioxidant enzymes, like glutathione and superoxide dismutase, which catalytically converts the free radical superoxide into hydrogen peroxide. 

The abundance of ROS in our cells has 2 components:


Production of ROS
Depletion of ROS by upregulation of antioxidant enzymes


Intracellular levels of ROS positively regulate levels of antioxidant enzymes like glutathione and superoxide dismutase (2). This means that more oxidative stress leades to more protection from ROS by antioxidant enzymes. This is why exercise, while increasing ROS levels, actually protects against them.

ROS are also produced during the cooking of food, especially meat (3). This applies to any type of cookware, any method of heating of any food: protein, carbohydrates, fats. 


'For example, it only takes a few hours at 70C to have the same extent of autoxidation which at room temperature requires months (4)'


Intracellular ROS are unavoidable. They are produced by normal metabolism, exercise, cosmic radiation, during the consumption of food. Balancing this are endogenous antioxidant enzymes. The antioxidant power of glutatione exceeds any known nutritional supplement (5). 

Exercise is an extremely effective upregulator of antioxidant enzymes, eclipsing any antioxidant supplement or change in cookware. Regular physical activity will most likely be the best prevention one can take against ROS induced genotoxic oncogenesis.