"The groundwork of all happiness is health." - Leigh Hunt

Why do cancer cells go dormant?

Cancer is at all times regarded as something that happens quickly and uncontrollably, but this view will be incorrect. New evidence shows that cancer alternately uses “accelerators” and “breaks” to survive.

If you plot the expansion of prostate cancer tumors over time, you get a graph that appears something like this:

Figure 1. An example of prostate cancer progression.
Modified from: http://www.cell.com/trends/molecular-medicine/fulltext/S1471-4914(15)00034-9

The graph shows that prostate cancer cells alternate periods of rapid growth with periods of dormancy. In the instance above, the tumor will grow to the purpose where it begins to cause symptoms and the patient seeks treatment – which normally involves cutting out the tumor.

Surgery is usually effective but, for some unlucky patients, their cancer will return. Currently, it is usually treated with hormone therapy and chemotherapy. But even these treatments don't at all times cure the cancer. For some patients, the cancer comes back after a period of remission.

During periods of indolence, which might last several years, the patient will often haven't any symptoms and the tumor won't be detected using normal diagnostic tools. Until recently, we knew little or no about these periods. However, research from my group and other scientists shows that cancer dormancy is a critical time for tumor growth.

Risks of cancer dormancy

To understand why heterogeneity is useful to cancer cells, we'd like to look at the aspects that may inhibit tumor growth. Cancer cells face three predominant challenges to their survival and growth. First, they should Tricking the immune system, which is in a position to eliminate most tumors. Second, they should survive anticancer treatments, and, third, they should invade distant organs and produce metastases.

Cancer is dormancy. Necessary To take care of all these challenges. During periods of dormancy, cancer cells reshape their genetic makeup and prepare for the following phase of growth. Without inactivation, cancer cells cannot survive in a brand new environment or turn into immune to immune system attacks. So it will be important to know how you can detect dormant cancer cells, and how you can kill them.

Although the detection of inactive cells just isn't easy. Inoperable tumors are sometimes small and don't cause symptoms, so patients are sometimes unaware of them and unable to “see” them with traditional diagnostic tools. In addition, dormant cancer cells are sometimes in a slow metabolism mode, like hibernating animals. So even among the most advanced diagnostic techniques, similar to PET scans, often miss dormant tumors.

Dormant cancer cells have some similarities with hibernating animals.
Break P Kent/Shutterstock.com

Diagnosis and treatment

So how will we detect these dangerous sleeper cells? Fortunately, latest studies are shedding light on the characteristics of dormant cancer cells. For example, our research, in collaboration with BC Cancer Agency In Canada, RNA produced by dormant and proliferating cancer cells has been observed. RNA is an important molecule that carries genetic information from DNA (the blueprint) to proteins (the workhorses of cells).

We have shown that some small RNAs are Specifically expressed by inactive cancer cells. Because these RNAs will be measured in urine and blood samples, we, and others, are attempting to develop latest diagnostic tools to detect these molecules. If we succeed, we'll have the option to develop blood or urine-based diagnostic kits that can help doctors discover inoperable tumors before they will effectively treat them.

Once dormant cancer cells are identified, they should be eliminated. Unfortunately, because these cancer cells are metabolically inactive, they're less more likely to be killed by conventional chemotherapy, so that they are difficult to focus on. Difficult, but hopefully not inconceivable.

A lot of latest studies show that inactive cells can have weak spots. For example, experiments show that some Non-steroidal anti-inflammatory drugs May prevent dormant cancer cells from “waking up” to form metastases. If clinical trials confirm these findings, we may soon have the option to supply patients treatments that specifically goal dormant cancer cells.