HELSINKI, July 3 (Xinhua) -- A new Finnish study shows that even a 30-minute exercise can increase the proportion of tumor-killing white blood cells in breast cancer patients' bloodstream.
According to a press release published by the University of Turku on Wednesday, twenty breast cancer patients who had just been diagnosed but had not yet started their cancer treatments participated in the study.
During the study, the patients pedaled a bicycle ergometer for 30 minutes at a resistance of their own choosing. Blood samples were taken from the patients at rest before, during, and after pedaling.
The results of the study revealed that during exercise, the amount of several different types of white blood cells increased in the bloodstream. The numbers of cancer-killing cytotoxic T cells and natural killer cells increased the most.
"We found that during the exercise, the number and proportion of cancer-destroying cells increased in the bloodstream, while the proportion of cancer-promoting cells either stayed the same or decreased," said Tiia Koivula, a doctoral researcher at the University of Turku, in the press release.
Koivula added that in preclinical studies, cancer-destroying cells have been observed to migrate into the tumor area.
The study also found that the larger the tumor, the less the number of natural killer cells increased.
White blood cells, the cells of the human immune system, fight against cancer, bacteria, and viruses. However, not all white blood cells destroy cancer cells; some can even promote cancer growth. The most important cell types that destroy cancer cells are cytotoxic T cells and natural killer cells. Those that support cancer growth include regulatory T cells and myeloid-derived suppressor cells, explained the university in the press release.
