Unravelling the genetic code of cancer
26 Mar 2012 by Evoluted New Media
Sequencing of two hereditary breast cancers caused by a faulty BRCA1 gene have revealed surprising results – the genetic code of the two tumours looked almost entirely different from one another.
The study from the Breakthrough Breast Cancer Research Centre at the Institute of Cancer Research (ICR) also produced preliminary results identifying three new breast cancer genes
“This research has big implications for how we treat hereditary breast cancer in the future,” said Professor Jorge Reis-Filho. “We often consider patients with a faulty BRCA gene as one group but our work shows that each tumour can look very different from each other genetically.”
“Now we understand this, we can start to identify the best treatment strategies to save more lives of hereditary breast cancer patients.”
BRCA1 germline mutations have a high risk of early-onset breast and ovarian cancer – in 80% of cases that are oestrogen receptor (ER) negative, and in 15% ER positive. Scientists looked at two tumours caused by a faulty BRCA1 gene – one was ER negative and one ER positive. They characterised the genetic landscape of BRCA1 cancer at base pair resolution with whole-genome massively parallel sequencing.
They tracked the genetic mutations in both tumours and found one similarity in addition to the initial BRCA1 fault – all other mutations were different. In addition, the ER negative tumour had twice as many mutations as the other underlining the differences that have occurred in their DNA.
Based on these results, the scientists scanned the genome of another groups of breast cancers and identified three genes which are altered in several other tumours – DAPK3, TMEM135 and GATA4. Although these genes have not been linked to breast cancer before, they are tumour suppressor genes which when mutated could be involved in causing breast cancer or driving its growth.
“It’s exciting to find new genes which could be involved in causing and driving breast cancer ,” said Dr Rachel Natrajan. “Now these have been identified we have to do more to work out the role that they play. Ultimately this knowledge could help us develop new treatments that target the specific defects of each patient’s disease.”
The results were published in the Journal of Pathology.
