What scientists mean by “heterogeneity” and why you should care

The term “diversity” is frequently circulated in our modern world. We are all different: we look different, have different personalities, and like different things. This is easy for us to understand and accept, yet it is only recently that this truth has been acknowledged in for example cancer drug development. Instead of trying to find the one magic pill, that will cure cancer, we have started to realise that cancer is a heterogenous (or in other words: diverse) disease. It is adaptable, ingenious, and more than a match for a one-size-fits all approach to cancer therapy.

Melanoma, an aggressive form of skin cancer, is especially complex. The DNA of these tumours are peppered with the imprints of sun exposure including thousands of DNA mutations. These mutations make each melanoma cell slightly different from the next. Further, each time a cell divides, there is a slight chance for it to acquire a mutation. These mutations could make it fitter, thus more aggressive and harder to treat. This process could happen anywhere, at any time and for any cell. This promotes heterogeneity and makes our attempts to treat the disease much more difficult.

Heterogeneity is important to consider not only for the tumour itself, but also with regards to the immune cells surrounding the tumour. These cells are important in keeping cancers in check (more info here or here) and potentially also in treating them. Approaches such as immunotherapies train a patients immune system to seek out and kill tumour cells with mutations rendering them different from normal cells. It’s a constant battle between cancer cells trying to avoid being recognised, and immune cells being alert, able to recognise and act when encountering such cells. Without certain immune cells, it would be an extremely one-sided fight with the advantage to the cancer.

I want to better understand how specific types of immune cells contribute to melanoma development (or better yet, stop it). Our immune systems are extremely complicated networks of different cells with their own special powers, that we don’t yet have enough knowledge about to fully grasp. I’m hoping my research could lead to an increased understanding of the role some specific immune cells play in melanoma development. By knowing more, we could potentially improve the future development of novel immunotherapies.

Written by Sofia Chen, ESR07