The chronically stressed mice had decreased immune function and experienced
tumor development significantly earlier than the non-stressed mice.16 Other mouse studies of
ovarian cancer showed that chronic stress resulted in increased cancer growth as well as increased angiogenesis, the process with which cancer forms new blood vessels to feed itself nutrients for growth and metastases.17 Chronic stress has also been shown to decrease our body's ability to mount an
attack against foreign invaders, including viruses.18 As we know that several viruses can cause cancer (HPV and cervical cancer, and EBV and nasopharyngeal cancer), we can extrapolate that any decrease in immune function could increase cancer risk.