Study sheds new light on the genetic of breast cancer
An international group of scientists has managed to present a clear picture of the mutations in genetic material involved in breast cancer. The study has been described in academic circles as a milestone in the field. It is estimated that it will pave the way for improved preventive and curative measures against the disease. The conclusions of the study were presented in an article in the prestigious academic journal Nature in May. Two Icelandic scientists, Professor Jórunn Erla Eyfjörð, and Post-doc Ólafur Andri Stefánsson, both at the Biomedical Centre of the University of Iceland, worked on the study and one of the study's main leaders, Serena Nik-Zainal of the Sanger Institute in the UK gave a talk on the research at a seminar in honour of Jórunn Erla on 6 May.
This is the most extensive study in the field of the genetics of breast cancers so far - including research on all the genetic material in 560 breast cancers - and how it has been affected by mutations. Carcinogenic mutations were discovered in 93 genes; i.e. 93 genes that can change a healthy breast tissue cell into a cancer cell. A mutation in one such gene in a healthy cell can contribute to turning it into a cancer cell. The genes are all significant; however, their importance in the formation of cancer varies when the whole group is taken into consideration. Thus it was revealed that around 60% of all the key mutations in breast cancer can be attributed to only 10 genes.
Icelandic BRCA2 mutation causes identical tumour development to others
Mutations in genetic material leave a certain pattern or fingerprint in the genetic material, it was thus possible to define 12 different types of damage causing harm and manifestation of disease. The cause of the 12 different fingerprints were in some cases known, for example reordering patterns in connection with mutations in genes known as BRCA1 and BRCA2, but most cases of hereditary breast cancer involve mutations in those genes.
Jórunn Erla Eyfjörð's research team had earlier identified a mutation in the gene BRCA2 999del5 in Iceland and shown a connection with increased risk of breast cancer in Iceland. The research discussed in Nature confirms that this mutation has the same effect on tumour development as other BRACA2-mutations. The research also confirms that BRCA2 999del5 tumours are subdivided into subcategories of varying severity. This effect manifests in the reordering patterns of genetic material in Icelandic BRCA2 999del5 gene carriers.
It is noteworthy that some patterns are linked with the bodies defence against viral infections. Defence systems developed to break down viral DNA can in some cases cause damage to their own genetic material.
Further research is needed to understand the disease better, however, this in depth analysis of mutation patterns in tumour tissue will hopefully open up the field for new options in diagnoses and specialised treatment.
Transgenerational epigenetic inheritance plays an important role in breast cancers
An analysis of epigenetic inheritance changes were also a part of the research. Ólafur Andri Stefánsson, Post-doc at the Cancer Research Laboratory at the Biomedical Centre at the University of Iceland, was involved in this aspect of the study. Epigenetic inheritance are factors controlling how genetic material is used, essential in the development and specialisation of cells. Through epigenetic inheritance genetic material is "labelled" in order to specify which parts of the material is to function at each time. The study showed that the BRCA1 gene is not only made passive through mutation in the gene, but also through epigenetic inheritance. This confirms the conclusions in Ólafur Andri's doctoral thesis, under the supervision of Jórunn Erla. The BRCA1 is thus rendered passive in a much larger group of patients that only those with a mutation in the BRCA1 gene.
All the information provided by the study will now be made accessible to researchers in Universities, pharmaceutical companies, and biomedical companies who can use them to develop more specialised pharmaceuticals and therapeutic options.
Jórunn honoured for her contribution to cancer research
A large number of scientists from many leading scientific institutions around the world in the field of cancer research were involved in the study discussed in Nature, and a more detailed account of the research appeared in the journal Nature Communications.
The study was led by Mike Stratton and Serena Nik-Zainal, both of the Sanger-institute in Cambridge. Nik-Zainal, a highly respected scientist, came to Iceland early May to participate in a seminar in honour of Jórunn Erla Eyfjörð, celebrating her seventieth birthday. The two scientists have collaborated fruitfully through the years.
Jórunn has studied breast cancer for decades and participated in highly successful international cooperation. She has published a number of articles in many of the world's most prestigious scientific journals. Furthermore, she has supervised a number of graduate and doctoral students at the University of Iceland, participated actively in administration duties, and served on the professional interest group of the Swedish and Finnish Science Academies. In 2006 she was presented with the Ása Wright award by the Icelandic Academy of Sciences, and in 2012 she received the University of Iceland's award for outstanding contribution to science.
At the seminar in honour of Jórunn, Alan Ashworth, the head of the Helen Diller Family Comprehsive Cancer Center at the University of California San Francisco, delivered the keynote address along with Serena Nik-Zainal. Ashworth was part of the research team that discovered the BRCA2 gene in 1995 and has for a long time worked on pharmaceutical therapies for cancer based on the mutation of the gene.
Besides Nik-Zainal and Ashworth a number of Jórunn's colleagues and students delivered presentations at the seminar.
