"Up until very recently, all patients with breast cancer were basically given the same therapy.
"We now clearly know that's not the right way to do things."
Professor Peter Rigby, chief executive of the Institute of Cancer Research, believes that recently the way treatments for cancer are being researched has completely changed.
And this, he thinks, is because of great strides made on how scientists are able to understand the genetic code.
In 2003, the Human Genome Project succeeded in sequencing the human genome to 99.9% accuracy, allowing scientists to "read" human DNA. Since then, researchers have been using this so-called roadmap to find a correlation between certain genomes and cancer.
This means that, in theory at least, cancer could be treated on a molecular level rather than using current therapies - such as chemotherapy or surgery - which damage many healthy cells along with those which are cancerous.
A 'new era'
And Professor Paul Workman, director of cancer therapeutics at the institute, agrees "there's no doubt that the new molecular-targeted therapies have much less severe side effects than the old-style cytotoxic (cell-killing) therapies."
For patients with the disease, this could herald a new era for cancer treatment.
"Patients will be treated in a way where hopefully the therapy will be very precisely matched to their tumour," says Professor Rigby.
There are few areas of medical and scientific research with a higher profile than cancer. According to the Sanger Institute, one in three people in the western world develop cancer and one in five die of the disease.
At the Institute of Cancer Research, £90m a year - much of which is from charitable sources - is spent predominantly on studying the genetic causes of cancer and using that knowledge to inhibit the disease.
Professor Paul Workman says: "The future of cancer, many of us feel, will be less about treating a whole range of tumours that happen to be breast cancers, but more we'll be describing cancers by the genes that are altered in that patient.
"Many of the drugs that we develop may work on - say - 10% of patients with lung cancer and 20% of patients with breast cancer that have the same [genetic mutation].
"They'll be working across cancers but more geared to the genetic defect in the cancer rather than the place where the tumour arose. It's a completely different approach to treating the disease."
The genetic code is split up into four letters - G,A,C and T - and each gene has a certain length, judged by the amount of letters contained in the gene. A typical gene may contain around 1,500.
The research works by finding mutations or abnormalities in the arrangement of the letters, says Professor Nazneen Rahman, a geneticist and clinician at the institute.
"It's a little bit like reading the whole works of Shakespeare and looking for one spelling mistake," she says.
And, to continue the simile, combing over Shakespeare's 884,647 words would make for even more tiring work if they had to be looked at on individual pieces of paper.
"Until relatively recently we could look at genes one at a time, then 10 at a time but what's happened over the last year or so is that new technologies have come around that will now allow us for the first time to look at 20,000 genes," she says.
It means that the days of having to make educated guesses and estimations about which genes are most likely to contain mutations have ended.
The mutations themselves do not indicate an increased potential to develop cancer - mutations make us different from our parents - but cross-correlating large samples of data from those with cancer means patterns begin to emerge.
And with just 1% of the human genome currently reached by drug therapies, the potential of this therapy could be astonishing.
"The technology is available," says Professor Workman. "The genes are available from the Cancer Genome Project, the understanding of how these genes work in cancer is still developing but we have enough information to make really effective inhibitors.
"I think it's now limited by finances and by the resources that can be put into it."