Impaired body clock speeds tumor growth in mice NEW YORK, May 01 (Reuters Health) The destruction of the body's natural rhythms accelerated the growth of cancerous tumors in laboratory animals, according to the results of a study. In mice whose body clocks--also known as circadian rhythms--were disrupted, "the body's defense system was apparently less able to control tumor growth," study co-author Dr. Michael H. Hastings, a neurobiologist with the Medical Research Council in Cambridge, UK, told Reuters Health. Hastings and colleagues Dr. Francis Levi and Elisabeth Filipski of the Paul Brousse Hospital and the University of Paris in Villejuif, France, and others were following up on recent reports that the disruption of the body clock of those who perform shift work seems to result in a higher propensity for cancer. In half the mice in the experiment, the researchers destroyed a part of the brain that controls the body's natural rhythms, including sleep-wake cycles as well as body temperature, hormone release patterns, immune response and metabolism. The remaining "control" mice received mock surgery. The mice with part of their brains destroyed lost proper functioning of their body's natural rhythms, remaining at a more constant level throughout the day and night. Hastings and colleagues then implanted tumors into all of the animals, and monitored the animals for tumor growth as well as long-term survival rates. The investigators found that the tumors grew two to three times faster in the animals whose rhythms had been disrupted. Those animals also experienced a significantly worse survival rate, living only 22 days after the tumor graft, compared with 26 days in the other group. The findings were published in the May 1st issue of the Journal of the National Cancer Institute. The study authors speculate that the part of the brain that controls the circadian rhythms may play a role in fighting off disease by its influence of the body's immune responses or hormonal fluctuations. "Human health is at its best when we have regular routines," Hastings said. "This need is magnified in cases of chronic illness, so regular schedules in patients are well advised." The findings may also point to ways that proper functioning of the body clock checks tumor growth. "If we can discover the usually rhythmic processes that in the normal mice slow down tumor growth," Hastings noted, "we can exploit them to 'soup-up' a patient's natural defenses--both to prevent cancer and to beat it should it become established." Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.