Previous studies had shown that calcium and vitamin D tend to reduce colon cancer risk. The study conducted over 92 patients revealed that supplementing diet with calcium and vitamin D appeared to boost the levels of a protein called Bax that controlled programmed cell death in the colon.
Lead researcher Veronika Fedirko said that more Bax might be pushing pre-cancerous cells into programmed cell death. "We were pleased that the effects of calcium and vitamin D were visible enough in this small study to be significant and reportable," she said. "We will have to fully evaluate each marker's strength as we accumulate more data," she added. Another study conducted by Dr Roberd Bostick, MPH, professor of epidemiology at Emory's Rollins School of Public Health, showed that high levels of calcium and vitamin D together increased the levels of E-cadherin, a protein that moderated colon cells' movement and proliferation. The study was conducted over 200-patients.
The third abstract on the same case-control study (5504) showed that high levels of iron in the diet were associated with low levels of APC, a protein whose absence in colon cancer cells leads to their runaway growth.
"The studies of colorectal biopsy samples are part of a larger effort to identify a portfolio of measurements that together can gauge someone's risk of getting colon cancer," said Bostick.
The findings on biological markers that could influence colon cancer risk would be presented in three abstracts at the American Association for Cancer Research meeting in San Diego.