Cancer has potential on-off switch: study

Researchers, including one of Indian-origin, have proposed that an "on and off" epigenetic switch could be a common mechanism behind the development of different types of cancer.
Epigenetics is the phenomena whereby genetically identical cells express their genes differently, resulting in different physical traits.
The current paradigm states that cancer develops from environmental and genetic changes to cancer progenitor cells. These changes are the result of mutations, exposure to toxic substances or hormonal imbalances.
"If we believe that everything in nature occurs in an organised fashion, then it is logical to assume that cancer development cannot be as disorganised as it may seem," said Sibaji Sarkar, instructor of medicine at Boston University School of Medicine (BUSM).

"There should be a general mechanism that initiates cancer progression from predisposed progenitor cells, which likely involves epigenetic changes," said Sarkar.
The existence of this epigenetic switch is indirectly supported by the fact that tumors develop through different stages, researchers said.

When cells rapidly grow during cancer progression, they become stuck in their current stage of development and their cell characteristics do not change.
This is the reason that there are so many types of leukemia - the characteristics that a leukemia cell possesses when it begins to rapidly grow and expand are characteristics that it will keep until the rapid growth stops.

"If we believe that all of the irreversible changes, mutations and effects of carcinogens make cells rapidly grow, then the mechanism that allows cells to stop growing and assume new changes in character must be of great importance," added Sarkar.
"The study of cancer progression is key to understanding how cancer cells continue to differentiate," said Sarkar.
During cancer progression, there are different stages of rapid growth and differentiation.
The control that allows for this switch between growth and differentiation can only be achieved through reversible mechanisms, such as epigenetic changes.
The research was published in the journal Anticancer Research and Epigenomics.