The Human Breast Really Is Best: The 21st Century Approach to Breast Cancer Research

While it is thought that less than 5 percent of breast cancer cases are related to a woman's genes and many cancers are largely preventable -- approximately 42 percent of new breast cancer cases in the UK and 38 percent in the US could be prevented.

This month I have been one of countless people around the world wearing a pink ribbon in support of breast cancer awareness. Together we are shouting about the importance of being breast aware. But we're also searching for answers for how to overcome what remains one of the greatest challenges in modern medicine.

When the Breast Cancer Campaign tells me that "breast cancer can be overcome by 2050", I want to believe it. Sure, advances in early detection and treatment mean the number of women dying from breast cancer has begun to go down in some developed countries in recent years. We now have drugs that weren't available before, and we are aware of risky lifestyle factors.

But let's not get too excited. Breast cancer remains by far the most frequent cancer among women and the most common cause of death from cancer in women worldwide. An estimated 1.5 million women globally were diagnosed with breast cancer in 2010, and breast cancer incidence has skyrocketed. In England, for example, incidence has increased by 90 percent since the 1970s while incidence rates in Australia and North America are among the highest in the world. China and other developing countries are experiencing not only a surge in incidence but in deaths from breast cancer too.

While it is thought that less than 5 percent of breast cancer cases are related to a woman's genes and many cancers are largely preventable -- approximately 42 percent of new breast cancer cases in the UK and 38 percent in the US could be prevented -- research efforts are dominated by attempts to 'model' women with breast cancer on genetically manipulated mice, or mice with artificially introduced advanced cancers.

These efforts are costly: The United States spent approximately $625 million of public money on breast cancer research in 2011, and the United Kingdom's funding has increased by 110 percent in less than a decade. But when one looks closely at what goes on in laboratories under the banner of breast cancer research, and in particular at the therapeutic return on these millions invested, concern begins to creep in.

Take Herceptin, for example, breast cancer's poster drug. It is derived from mouse antibodies and was developed using animal models. Herceptin proved to be the rarity among thousands of other drugs developed in mice that failed to work in people. Out of around 200,000 published studies on novel cancer treating drugs developed in animals, 90 percent of those agents that showed anti-tumour effects in other species subsequently failed in human trials.

Clearly, Herceptin has helped some patients. Yet it can only be offered to less than one in five women with breast cancer, those who exhibit a certain type of protein in their cell membranes, And even amongst this small group of women, the majority of cancers that initially respond to Herceptin begin to grow again within just one year. Most don't respond at all, with many patients experiencing all the side effects of Herceptin with no benefit.

While these side effects are horrendous enough, one adverse side effect had potentially fatal consequences. Heart-related risks to humans associated with taking Herceptin were not revealed in animal safety tests.

One major problem with using mice as breast cancer models is that their immune systems reject the human cancer cells transplanted into them. To overcome this, scientists attempt to study human cancer in mice bred without immune systems. But this introduces a fundamental distortion: in the human disease, the immune system is active and influences the cancer's progression and outcome. Also, implanting fully grown human tumour cells under the skin of a mouse is not the same as the gradual way cancers develop in a human breast. Nor can this process replicate the complex interactions between tumour cells and the surrounding human environment.

The fact that these artificial tumours in mice seldom spread to other parts of the animal's body - which in people is the main factor affecting chances of survival - is just one more way in which these cell grafts in mice fail to accurately reflect human breast cancer.

Human breast cancer is a complex disease -- no two women's breast cancers are alike. In fact, breast cancer is actually a mélange of 10 subtly different diseases, and no animal model has yet been found to reproduce this multifaceted disease in the laboratory. Research based on mice may well help us cure cancer in mice, but all the while, the long-awaited cure for human breast cancer eludes us.

Everyone living with breast cancer deserves hope, not just a very small percentage of patients. To get to grips with breast cancer means it is time to get to grips with 21st-century science. The cassette-playing Walkman now appears absurdly old-fashioned alongside the slick simplicity of iTunes downloads, and computers the size of double-decker busses have been replaced by pocket-sized tablets. Technology has replaced its forerunners in so many areas of our lives with something speedier, more efficient and better. Human health research should be no exception.

When it comes to a disease like breast cancer, the human breast really is best. There are now banks of human breast cancer tissue, lactating breasts on a chip and computer-simulated virtual breast cancer patients that mean we can begin to understand the underlying pathways that initiate and progress breast cancer in humans at a cellular, molecular and chemical level. With modern and human biology-based tools, we can say goodbye to last century's flawed animal models in favour of more sophisticated and relevant approaches for studying -- and finding cures for -- diseases in our species.

So this month, as we wear our pink ribbons, let's be aware that breast cancer research needn't remain a medical challenge forever. While traditional medical research has had some success for some patients, if we invest in and implement today's human-relevant technologies, we can accelerate progress in breast cancer research for the benefit of everyone.

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