Why haven't we found a Cure to Cancer yet?

by Miriam Kathleen Gomez

Why is it so difficult to treat cancer?

These are the questions that very often cross our minds.  As a cancer researcher, I often wonder if curing cancer will ever be possible. We have come so far in research with new techniques and instruments being developed every day making things like sequencing the whole genome possible. We have successfully eradicated diseases like small pox . . . . . . . but not cancer.

Why is it? Why is cancer so different from other diseases?

Cancer cells are cells from the body that have acquired an ability to grow uncontrollably. Most of the times when a normal cell converts into a cancerous cell the immune system of the body detects the change and kills the cancerous cell, but sometimes the cancer cell can disguise itself as a normal cell and go on dividing unchecked thus forming a tumour.

One of the reasons curing cancer is difficult is because cancer is not one disease with one magic cure. Just like all cells of the body are different each cell when becomes cancerous is different. Since normal body cells convert into cancer cells, so there could be as many types of cancers as types of cells in the body. Despite originating from different cells, almost all types have some common features called the hallmarks of cancer, such as the ability to evade programmed cell death, ability to induce production of blood vessels to feed itself, evasion from immune system and ability to invade other tissues. There are also some molecular signatures that are common for different types of cancer.

Even with all these similarities cancers that have originated from same cell type can be different from each other owing to different genetic changes and molecular signatures.  Adding more to this complexity, is diverse population of cells in a single solid tumour bearing different molecular signatures.

Most cancers are treated with a combination of surgery and chemotherapy in an effort to completely get rid of the disease. Newer therapies like hormone therapy, immunotherapy and targeted treatments are finally finding a way into the clinic. In most cases these treatments are effective increasing the quantity and quality of life of the patients, but it does not work on all the cases.

So is cure even possible?

What we can start with is finding better models to study all the different types, because we still do not understand most of the cancers. Most researchers use cell lines, which are cancer cells grown on plastic in the lab. Although the cells are grown in an environment to simulate bodily conditions but this system might lack the complexities of tumours. This difference is one of the major reasons cancer treatments fail in the clinic so very often. To make it difficult, cancers are constantly adapting to changes in their environment, and when treated with drugs develop resistance, giving rise to a new more resistant disease. To be able to better understand the treatments and how they would work in tumours inside the body, we need systems to duplicate this tumour complexity.

Image: Left is a microscopic view of the HeLa cell line, which was one of the first cancer cell line to be established by George Gey. Right: Dulbecco's Modified Eagle Medium and specialized containers used to grow cell lines.

The future of cancer treatments might seem bleak in the light of this post, but the good news is that we are making progress and mortality for most cancers has dropped worldwide. Cancer free survival of patients has also increased. Each day millions of motivated cancer researchers learn a little more about cancers and their treatment. Multiple treatments have emerged in recent years which are specifically targeted for one cancer type, thus aiming to get better response in patients. Hopefully in near future after getting a better insight into cancer we will have personalised treatments tailored to take into account the origin, type, molecular signature and patient’s genetics.

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Miriam K. Gomez is a Ph.D student at edinburgh cancer research centre, Institute of Genetics and Molecular Medicine, University of Edinburgh. Passionate about the idea 'science is for everyone', she likes to engage with the general public to make science understandable and accessible to all.

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