Boosting vitamin C levels may help curb leukemia risk

New York, Aug 22 (IANS) Boosting daily requirement of vitamin C may be helpful in curbing the development of leukemia -- a deadly blood cancer, a study has found.

Previous studies have shown that people with lower levels of ascorbate (vitamin C) are at an increased cancer risk but the reasons were not fully understood.

The new study, published in the journal Nature, showed that stem cells soak up unusually high levels of vitamin C, which then regulates the cell function and suppresses the development of leukemia.

"Stem cells use ascorbate to regulate the abundance of certain chemical modifications on DNA, which are part of the epigenome," explained Michalis Agathocleous, from University of Texas Southwestern Medical Centre.

"The epigenome is a set of mechanisms inside a cell that regulates which genes turn on and turn off. So when stem cells don't receive enough vitamin C, the epigenome can become damaged in a way that increases stem cell function but also increases the risk of leukemia," Agathocleous added.

This increased risk is partly tied to how ascorbate affects an enzyme known as Tet2. Mutations that inactivate Tet2 are an early step in the formation of leukemia.

Ascorbate depletion can limit Tet2 function in tissues in a way that increases the risk of leukemia, the researchers explained.

Importantly, the findings have implications for older patients with a common precancerous condition known as clonal hematopoiesis, which puts patients at a higher risk of developing leukemia and other diseases.

"One of the most common mutations in patients with clonal hematopoiesis is a loss of one copy of Tet2. Our results suggest patients with clonal hematopoiesis and a Tet2 mutation should be particularly careful to get 100 per cent of their daily Vitamin C requirement," said Sean Morrison, Director at the varsity.

"Because these patients only have one good copy of Tet2 left, they need to maximise the residual Tet2 tumour-suppressor activity to protect themselves from cancer," Morrison noted.