What Is Cancer?

Watching 6 clips from the Emperor of the Maladies (cancer) was interesting as I really learned a lot more about this complex disease.

My five big takeaways from these wonderful clips answer the questions below/

How is a cancer cell different than a normal cell?

Cancer cells evolve at a much faster rate than normal cells; they are very responsive to adapt to changing environments (e.g. the influx of drugs). The worst, disease-causing difference is that cancer cells divide uncontrollably and selfishly use up the body’s resources. There is no control such as apoptosis (programmed cell death); thus, the patient becomes very sick when fighting cancer.

How has cancer treatment evolved as scientists have learned more about cancer?

Scientists learned that there are about 200 oncogenes which are made of several different groups. A dozen of those 200 oncogenes works together in certain pathways to cause a specific type of cancer. Scientists learned that treatments targeting those genes would take care of a vast majority of cancer, so now their research is more streamlined and focused. Finally, they learned that with new powers, the cancer cells have their own Achilles heels; they discovered that the best way to attack cancer cells is to use combination therapy (a multitude of drugs) in the fight. If a cancer cell adapts to one drug and evolves a certain way, hopefully, another drug will take care of it.

What steps can an individual take to prevent cancer?

While 40% of cancer causes are unknown, smoking/obesity/radiation/sunlight/asbestos are all known cancer causes. For example, if society takes some of these preventative steps (like not smoking and exercising regularly), cancer cases (like lung cancer) will go down by 50%.

Why has it been so difficult to find a cure for cancer?

Drugs used in clinical trials that have shown some positive results have rarely been able to completely eradicate cancer as the cancerous cells mutate and become resistant to those drugs. Thus, the idea of treatment must be changed from static to dynamic, evolving as the cancer cells evolve.

What does Richard Klausner mean when he says cancer is like evolution in a bottle?

Cancer cells rapidly mutate; Richard Klausner was using a good metaphor to describe this rapid rate of change. When it comes to evolution, cancer cells have so much power to change and adapt that he described the rate as a billion times the speed of evolution. The power can be compared to compressing Earth’s whole evolutionary history in a single cell and speeding it up drastically. Thus, cancer cells have so much potential that scientists face great difficulty in finding viable, long-term, complete treatments for cancer.

Cytoplasmic Streaming

Experiment

An elodea leaf sample was prepared and examined under a compound light microscope with magnifications of 10X, 40X, and 400X respectively. Coarse adjustment was used to optimize viewing under 10X. Then, fine adjustment was used along with a little coarse readjustment under 40X magnification. Finally, fine readjustment was employed under 400X to observe cytoplasmic streaming. Below is a picture of the specimen containing several elodea leaf cells with labeled cellular components. Other organelles that weren’t pointed out in this picture weren’t visible as they were most likely covered by chloroplasts or due to the low magnification.

Results

The ultimate goal of this experiment was to capture a video of cytoplasmic streaming where the cytoplasm rearranges the organelles when its fluid runs through the cell in a particular direction. With reference to the picture above, cytoplasmic streaming moved most of the chloroplasts to the plant’s cell wall (hence, the green coloration around the cell wall). Chloroplasts are transported by cytoplasmic streaming near the cell wall (as observed in the photo above) to maximize light absorption and reduce carbon dioxide and oxygen diffusion time. Below is the captured video of cytoplasmic streaming. Look at the circled chloroplast in the video to see an example of cytoplasmic streaming; the chloroplast shifts from one side of the cell to another. Click on “Cytoplasm streaming” to view this video directly on YouTube.

In this experiment, there was evidence supporting the cell theory.

1. The cell was the unit of structure/function/life. Each elodea leaf cell looks like a rectangular box. The elodea leaf is made of many cells as they have low surface area to volume ratios and work efficiently. The group of cells forming tissues; different tissues make up the organ, which is the leaf in this case.
2. All living things are made of one cell or more. The elodea leaf sample had many cells, that are visible as green rectangles with a light blue/transparent fluid in their interior, called the cytosol.