Updated on 20 November 2013
Cold changes the way cancer cells grow and spread in mice
Singapore: A study by Dr Elizabeth Repasky and colleagues at the Roswell Park Cancer Institute in the US found that cold changes the way cancer cells grow and spread in mice. The research has been published in a paper in the Proceedings from the National Academy of Sciences (PNAS).
The study found that that mice living in a relatively cold environment of around 22°C had cancers that grew more quickly and aggressively than mice living at a nice thermally comfortable temperature of around 30°C. A cold environment boosted the growth of several different types of cancer, including breast, skin, colon, and pancreas.
It did not matter if mice had lived in the cold for a lifetime before they got cancer. A chilly exposure even after their cancer had become established still made their tumors grow more quickly.
The body's anti-cancer responses are mostly driven by the immune system's T cells, which recognize and destroy tumor cells based on the altered proteins they produce. Tumors often react to a T-cell attack by producing signals that trick the body into suppressing these immune cells. This battle continues until one side outpaces the other. A lot of anti-cancer treatments given in the clinic help to swing the balance in favor of the immune system.
Both the cold and the comfortable mice had the same numbers of potential cancer-fighting T cells when they were healthy. But the tumor-seeking T cells in the comfortable mice were quicker and better at burrowing into the tumor to attack it. They also secreted more cancer-fighting substances than the cells from cold mice. In the tumors of cold mice, there were greater numbers of suppressive cells capable of shutting down normal immune responses. Cold temperatures, then, shifted the body's response from fighting the tumor to accepting it.