More and more links are being made between blood glucose and a variety of cancers. It's known as the "Warburg effect". Here's a very recent article regarding glucose and breast cancer.
Researchers have shown that aerobic glycolysis -- glucose metabolism in the presence of oxygen -- is not the consequence of the cancerous activity of malignant cells, as has been widely believed, but is itself a cancerous event.
Bissell and her Japanese collaborators believe their findings help explain why hyperglycemia in diseases such as obesity and diabetes can raise the risk of breast and other cancers. In addition, these results may also help explain why anti-diabetic drugs, such as metformin, which lower blood glucose levels, have been linked to lower cancer risks and mortality.
I've never posted on the cancer forums so forgive me if this is already common knowledge.