London: For the first time, scientists
have identified master cells that give birth to deadly skin
cancers, a discovery that could pave the way for new
treatments for the potentially fatal disease.
Researchers at the Stanford University found the
`master cells` that are responsible for the growth of
malignant melanoma tumours -- the sixth common cancer in the
UK which affects more than 10,000 people every year.
The disease is caused by exposure to ultraviolet light
and numbers have quadrupled over the past 30 years as more
people enjoy sunshine holidays abroad or use tanning booths,
the Daily Mail reported.
Eight out of 10 melanomas are found at the early stage
when the condition is easy to treat by removing the tumour.
However, Dr Alexander Boiko, who led the research at
Stanford University, said the newly discovered `stem cells` in
advanced skin cancers were often missed by conventional
"Without wiping out the cells at the root of the
cancer, the treatment will fail," he said.
In recent years, scientists have discovered that a
subset of cancer cells lies at the root of many kinds of
tumour. These cancer stem cells can make copies of themselves
and differentiate into other cancer cell types.
Unlike normal cancer cells, stem cells are resistant
to radiotherapy and chemotherapy, allowing cancers to return
Cancer stem cells were first identified in blood
cancers, but have since been found in tumours of the bladder,
brain, breast and colon.
The latest study, published in the journal Nature, is
the first time they have been found in malignant melanoma.
"I didn`t know if melanoma would in fact have the
cancer-initiating cells," said Dr Boiko.
"I was completely unbiased, so I was actually sort of
surprised to find such a clear-cut answer. It fits exactly
what`s been discovered in the studies of other solid tumours."
While looking at samples of skin tumours Dr Boiko
discovered a distinctive subset of cancer cells. A marker on
the surface of the cell was previously found on stem cells.
When he transplanted these cells to laboratory mice,
he found they were much more likely to cause skin cancers than
other cells taken from the human tumour.
He also found that the cells self-renewed and turned
into different types of cancer cell.