Although stress does not create cancer cells, it may affect their growth by suppressing the activity of:

Corticosteroid hormones are produced during stress. The hormone is useful especially in enabling the body to cope with short periods of stressful situations.  However, when the hormone is produced for long periods, it tends to suppress the immune system.  The activity of Natural Killer cells involved in cancer regulation is repressed by stress hence allowing progression of cancer.

a. by using fur or clothes to trap heat energy near the body