Pancreatic cancer splits into four types, says genome study

Date: Feb-27-2015A new study that examines the extent of disruption to chromosomes that occurs in pancreatic

cancer suggests there are four subtypes of the cancer, dependent on the type of genetic

chaos.

The researchers classified pancreatic cancer according to patterns of DNA disruption in tumors.

The international team behind the study - including scientists from Cancer Research UK - hopes the

findings will lead to improved treatments for pancreatic cancer.

Pancreatic cancer is one of the most difficult cancers to treat. Fewer than 5% of patients survive

more than 5 years after diagnosis.

In the journal Nature, the researchers describe how they performed whole-genome sequencing

and analyzed variations in DNA patterns in 100 pancreatic tumors.

DNA is a long-chain molecule strung with chemical components called nucleotides that are like the

dots and dashes of the genetic code. An organism's DNA - the genome - is the instruction manual for

creating the organism. In humans, each cell has 23 pairs of chromosomes containing tightly packed DNA

molecules comprising around 100 million nucleotides.

Genes are a subset of a cell's DNA - while all our genes are made of DNA, not all of our DNA is

made of genes. Genes contain the instructions for making proteins - the workhorses of cells. Only a

small percentage of our DNA is made up of genes - the rest contains other types of instructions, for

example how to switch genes on and off.

When DNA is shuffled around - something that happens for all kinds of reasons, including errors in

copying the DNA when cells divide - the resulting mutations can cause genetic chaos, creating new gene

versions or causing genes to switch on and off at the wrong time.

Study says pattern and extent of DNA shuffling results in four types of pancreatic cancer

Fast facts about pancreatic cancer

Pancreatic cancer is more common in older people

Nearly 1 in 3 pancreatic cancers are thought to be linked to smoking

Symptoms include jaundice, pain in upper abdomen and significant weight loss.

Find out more about pancreatic cancer

The team in this new study found evidence of large chunks of DNA being shuffled around, which they

were able to classify according to the type of disruption they created in chromosomes.

The study concludes there are four subtypes of pancreatic cancer, depending on the frequency,

location and types of DNA rearrangement. It terms the subtypes: stable, locally rearranged,

scattered and unstable.

The researchers believe some of the mutations they found could be promising targets for new

drugs.

One of the study leaders, Andrew Biankin, a Cancer Research UK scientist at the University of

Glasgow in the UK, says despite many decades of research, we still face many obstacles in finding new

treatments for pancreatic cancer:

"But our crucial study sheds light on how the chaotic chromosomal rearrangements cause a huge range

of genetic faults that are behind the disease and provide opportunities for more personalized

pancreatic cancer treatment."

Patients with 'unstable' subtype of pancreatic cancer may benefit from platinum drugs

The team also found evidence to suggest pancreatic cancer patients may benefit from platinum-based

drugs - commonly used in chemotherapy treatments for testicular, ovarian and other cancers.

Until now, use of platinum therapy in pancreatic cancer patients has met with mixed results. But

this study suggests patients with the "unstable" subtype may be the ones most likely to benefit. Prof. Biankin notes:

"Being able to identify which patients would benefit from platinum-based treatments

would be a game-changing moment for treating pancreatic cancer, potentially improving survival for a

group of patients."

Meanwhile, Medical News Today recently learned about a new

drug delivery device that could transform the treatment of pancreatic, breast and other cancers

that have solid tumors. The new device uses an electrical field to drive chemotherapy drugs directly

into tumors, without having to rely on perfusion via the bloodstream.

Written by Catharine Paddock PhD

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.