A study published this past August by cancer researchers from Spain suggests that higher levels of Vitamin D (specifically the amount of Vitamin D receptors) can possibly help in early colon cancer cases by blocking a specific colon cancer progression pathway called Wnt/beta-catenin. Higher levels of Wnt/beta-catenin are thought to be responsible for the initiation of many types of colon cancer in humans. The study found that while Vitamin D receptors did not have an effect on the number of colon cancer tumors, higher levels of Vitamin D receptors did decrease overall colon cancer tumor load.
It does appear that in more advanced cases of colon cancers, the Vitamin D receptors are already significantly down-regulated and reduced.
The authors of the study suggest that Vitamin D receptor concentrations may offer addition treatment options in early colon cancers where the amount of vitamin D receptors have not been significantly reduced.
Vitamin D supplementation may also be a way to reduce or limit the growth of early colon cancer tumors by decreasing the overall tumor load of the colon cancer.
Larriba MJ, Ordóñez-Morán P, Chicote I, Martín-Fernández G, Puig I, et al. (2011) Vitamin D Receptor Deficiency Enhances Wnt/β-Catenin Signaling and Tumor Burden in Colon Cancer. PLoS ONE 6(8): e23524. doi:10.1371/journal.pone.0023524