A new drug, hitherto used for treating cancer attributed to inherited mutations in BRCA-genes, could be beneficial to up to 20 percent of patients with breast cancer. This is revealed in a new study by a group of international research scientists published in Nature Medicine on 13 March. Jórunn Erla Eyfjörð, professor emeritus at the University of Iceland's Faculty of Medicine, is affiliated with the research.
The study discussed in Nature Medicine is a continuation of extensive research on breast cancer published in Nature science journal in May last year. The new article in Nature Medicine focuses on deficiencies based on BRCA1 and BRCA2 genes. These deficiencies have for example been found in Icelandic research. The genes determine proteins that play an important role in DNA repair. Mutations in the genes BRCA1 and BRCA2 result in diminished repair in the so-called double-strand breaks, and are thus connected to increased risk of breast cancer as well as other types of cancers, such as ovarian, prostate and pancreatic cancers.
Inherited mutations in these genes are, however, rare and thus only explain a small fraction of breast cancer in the world. The research, published in Nature Medicine, examined 560 individuals with breast cancer in terms of mutations, instability and gene expression. The results were interpreted with a new model called HRDetct, that detects certain mutational- and rearrangement signatures in tumours. The study revealed the same pattern in tumours in considerably more individuals than those know to carry a congenital BRCA1 or BRCA2 mutation, thus revealing a larger proportion of individuals with breast cancer harbouring BRCA1/BRCA2 deficiency than hitherto appreciated. These individuals could possibly benefit from the same kind of treatment resources.
The so-called PARP inhibitors are drugs that have been designed to treat breast, ovarian and prostate cancer in individuals harbouring BRCA1/BRCA2 deficiency. Numerous clinical trials are being conducted using PARP inhibitors all over the world.
The study is multinational, developed from an international collaborative project; the International Cancer Genome Consortium – ICGC aimed at categorizing and defining all major cancers in humans. The project currently covered in Nature Medicine is based on extensive collaboration, development of methods and a new approach in processing large databases.
The research is a collaboration between a large group of research scientists from a few European countries, the Uniited States and Australia. The team leader of this complex task is Dr. Serena Nik-Zainal from Wellcome Trust Sanger Institute in Cambridge UK. Jórunn has collaborated successfully with Wellcome Trust Sanger Institute for many years, both with Mike Stratton, the institute's director, and Serena Nik-Zail, who gave a talk at a seminar in honour of Jourunn held at the University of Iceland in May last year, when the first article was published in Nature.