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Pancreatic cancer splits into four types, says genome study

Anew 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.

2015.02.27 08:21

 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 organisms 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 cells 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



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.

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