We all are aware, what a tumour is. There can be different types and variants of a tumour. To study them all under one umbrella a Pan-Cancer project was launched. It involved analysis of more than 2600 genomes of 38 different tumour types, creating a huge resource of primary cancer genomes. According to the Pan-Cancer analysis project, it intends to examine the similarities and differences among the genomic and cellular alterations found across diverse tumour types. Yet genome analysis has focused primarily on only 1-2% of the whole genome – the part that contains the code for making proteins. What about the rest? Does it also play a role in driving the disease?
The genetic drivers of cancer need to be discovered, to fully understand the mammoth disease, in order to cure the disease. And to bring an end to the suffering of cancer patients.
Joachim Weischenfeldt of the University of Copenhagen said “Decades of work has been focused on identifying the consequences of changes in the protein-coding part of the genome. Many cancers have no important mutations in the protein-coding part, but something is driving cancer. By inference, we suspect the non-coding part is playing an important role in these unexplained cases.”
As a part of the Pan-Cancer project scientists have analyzed whole-genome sequencing data. But now, what needs to be done is to analyze the non-coding sequence of the genome too. For which new statistical methods are to be developed by the scientists.
During the research, new drivers of cancer were observed, point mutations. Which is a genetic mutation where a single nucleotide base is changed, inserted or deleted from a sequence of DNA. But surprisingly, this was observed in the non-coding part of the genome. They also identified newly recognized driver rearrangements near genes called the AKR1C genes. This was interrelated with increased gene expression across lung and liver cancers.
However, these mutation drivers were found to be less frequent in the non-coding regions as compared to the coding regions. But the reason behind this may be the relatively less patient data available to analyze for some tumour types.
“We probably need an order of magnitude more genomes to really have a comprehensive understanding of all the mutations that drive cancer, and the complex mechanisms by which they form,” says Weischenfeldt. “As cancer is a disease of the genome, we ultimately want to be able to explain as many cancers as possible using genetics.”