Effect of magnetic fields on tumor growth and viability.

Breast cancer is the most common nonskin cancer and is the second leading cause of cancer-related deaths in women. Most methods of intervention involve combinations of surgery, chemotherapy, and ionizing radiation. Both chemotherapy and ionizing radiation can be effective against many types of cancer, but they also harm normal tissues. The use of nonionizing, magnetic fields has shown early promise in a number of in vitro and animal studies. Our study tested the effect of varying durations of magnetic exposure on tumor growth and viability in mice injected with breast cancer cells. Cancer cells were labeled through stable expression of firefly luciferase for monitoring of tumor growth and progression by using an in vivo imaging system. We hypothesized that magnetic field exposure would influence tumor growth and progression. Our results showed that exposure of the mice to magnetic fields for 360 min daily for as long as 4 wk suppressed tumor growth. Our study is unique in that it uses an in vivo imaging system to monitor the growth and progression of tumors in real time in individual mice. Our findings support further exploration of the potential of magnetic fields in cancer therapeutics, either as adjunct or primary therapy.