The Mystery of Cancer- Everything you need to know about the disease that has dominated research.

Whether it's a family member, a friend, just a stranger, chances are that you know someone who has developed cancer during their lifetime. Unfortunately, cancer is the second leading cause of death in the US, with 1 in every 2 women and 1 in every 3 men developing a form of this disease. 1.8 million diagnosed cases and 600,000 cancer-related deaths are projected in 2020, continuing a decline in both diagnosis and mortality rates.

Though cancer affects millions of families throughout the globe, there is still a lot of misconceptions and unknowns that linger about the disease. The goal of this article most of the questions you may have and inspire you to learn more about it.

So let's start with the basics!

What really is cancer?

Cancer is a result of the uncontrolled and rapid division of cells in a certain area of the body.

But what does this all mean…

Think about it like this: Everything within us is made of cells. Throughout our lifetime, from childhood to adulthood, we are constantly growing. This means that new cells need to be made to allow for this and also replenish cells that might be used up in the process. This is called cell division, a part of the long life timeline of a cell called the cell cycle that is mediated by physical and chemical factors that control a normal cell’s division and wellbeing. In each cycle checkpoint, the cell waits for a signal that ensures that everything in the process is going as it should be .

Cell Cycle

Cancer cells do not abide by these factors due to genetic mutations. Cancer cells t ignore these checkpoints or synthesize their own growth factors to move through the cycle. This allows them to divide at a faster rate and continue to survive even in circumstances where they are not supposed to.

Examples of Physical Factors Cancer cells don’t follow:

Anchorage dependence is the requirement for a cell to be in contact with a solid surface to divide. Meanwhile, density-dependent inhibition the requirement for a cell to stop dividing when it touches another cell from all sides. Cancerous cells do not follow these conditions.

Examples of Chemical factors Cancer cells don’t follow:

Growth factors- a group of molecules that trigger key events in a cell; they are responsible for telling the cell that it is ready to move on to the next stage of the cell cycle. Growth factors can be found at the G1, G2, and M checkpoints of the cell cycle.

Proto-oncogenes and tumor suppressor genes are two examples of these regulating factors that are essential to similar processes within a cell. Proto-oncogenes are responsible for growth factors, growth factor receptors, and cell signaling proteins; while, tumor suppressor cells are in charge of cell regulators, and regulate apoptosis, a cell’s self-destruction. Once these genes have been mutated, the cell can continue past the checkpoints unchecked.

How are tumors formed and classified?

As a result of these mutations, cancer cells grow uncontrollably into a mass called a tumor.

Tumors are classified into two groups, malignant and benign.

Differences between benign and malignant tumors.

Benign tumors are made up of excess cells that do not travel to other parts of the body but instead stay together in their area of origin not growing or growing slightly. Typically these cells do not reappear once the tumor has been removed. Benign tumors are not considered as dangerous as malignant tumors and in some cases harmless depending on the origin and size. The method of removal tends to be surgery though it may vary.

Malignant tumors are made up of cancerous cells that are detached from the original tumor and travel throughout the body, invading healthy tissue. These cells spread through the blood system in a process called metastasis; this makes it a lot more difficult to treat as a disease. The cells that spread out throughout the body contain similar mutations as those of the original tumor. When someone has a malignant tumor they are said to have cancer.

How are cancers classified?

Cancers are named based on the organ the tumor is found in and the progression of cancer (its stage) is specified using roman numerals.

There are different categories in that these cancers are classified in:

  1. Carcinoma

Carcinoma is the most common type of cancer. It is formed in epidermal cells, the cells that line the surfaces of the body such as blood vessels, urinary tract, and other internal organs. There are many types of carcinomas such as Adenocarcinoma, Basal cell carcinoma, Squamous cell carcinoma, transitional cell carcinoma. However, the most common types are Basal cell carcinoma (BCC), Squamous cell carcinoma (SCC).

BCC occurs in basal cells, cells found in the innermost layer of the epidermis. BCC can first appear as colored bumps, lesions, or patchings. BCC’s cancerous cells grow slowly and are not likely to appear after removal.

SCC, however, is more severe. This cancer occurs in squamous cells, cells that are responsible for material storage, filtration, and absorption in the epidermis. SCC appears in the form of flat sore cysts, patches, or ulcers, mostly on the skin that receives the most UV rays, often sunlight. These symptoms appear closer to the skin meanwhile BCC symptoms appear deeper down in the epidermis. Some forms of SCC can grow rapidly.

2. Sarcoma

Sarcoma is a type of cancer found in the bone and soft tissue such as blood vessels, lymph vessels, and fibrous tissue. There are more than 70 types of sarcomas therefore, the tumor’s progression, strength, and treatment methods vary from case to case. Symptoms vary on the type, however, lumps and drastic weight loss is common.

3. Melanoma

Melanoma is a type of cancer that occurs in melanocytes, cells in the upper layer of the epidermis that is in charge of making a pigment that gives the skin its color; this pigment is called melanin. This type of skin cancer is a lot more severe than both BCC and SCC, however, if detected early patients are expected to have a 98% 5-year survival rate. Similarly to SCC, growth is most likely to be found in areas that receive the most amount of UV radiation. Common symptoms are physical change in a pre-existing mole, development of a pigmented formation on the skin.

4. Leukemia

Leukemia is a type of cancer that is detected in the bloodstream and bone marrow. All blood cells begin as hematopoietic stem cells that then grow to develop into two types of cells, myeloid or lymphoid cells. Myeloid cells typically develop into red blood cells and lymphoid cells develop into white blood cells.

Comparison between normal blood cells and those with leukemia.

For white blood cells to grow into these specific categories, they must divide; therefore, leukemia cells develop when white blood cells begin to divide uncontrollably. These abnormal blood cells begin to crowd the bloodstream and bone marrow, taking up so much space that it is difficult for the normal blood cells to grow and divide. Because of this blockage, it is harder for oxygen to get to its tissues, control bleeding, etc.., often leading to other problems. This type of cancer does not form a solid tumor but float in small groups in the bone marrow and, eventually, the bloodstream.

Symptoms of Leukemia are easy bleeding or bruising, losing weight, fever, fatigue, etc. Treatment and severity can vary based on the type of leukemia. The most common types of leukemia are Chronic lymphocytic leukemia (CLL), and Acute myelogenous leukemia (AML).

5. Lymphoma

Lymphoma is a type of cancer found in the lymphatic system that is made up of lymph nodes, spleen, thymus gland, and bone marrow. The lymphatic system carries a liquid called lymph from body cavities into veins. Lymph passes through lymph nodes that spread throughout the body. Similarly to leukemia, it is a type of blood cancer.

Lymphoma begins in the lymphocytes that can be divided into T cells (thymus cells) and B cells (bursa-derived cells). Lymphocytes are specialized white blood cells, that help the body get rid of foreign threats and bacteria. Lymphoma occurs when these lymphocytes divide uncontrollably and crowd lymph nodes, making it harder for immune cells to move through the body.

There are two leading types of lymphomas: Non-Hodgkin lymphoma and Hodgkin lymphoma. Non-Hodgkin encompasses a large group of lymphomas that take place in the B or T cell. Hodgkin lymphoma specifically occurs in B cells that develop into a defective cell called Reed-Sternberg.

The difference between lymphoma and leukemia is that lymphoma generally affects lymph nodes while leukemia affects the bloodstream and bone marrow.

Hallmarks are swelling of lymph nodes and bone pain.

6. Brain and Spinal Cord tumors

A diagram summerizing 3 different types of brain tumors.
A diagram summerizing 3 different types of brain tumors.
Diagram summarizing different types of brain tumors

Brain and spinal cord tumors (intradural tumors) are tumors found in the skull or spinal column. Since these are both are key components in the nervous system, treating such tumors is particularly difficult because you risk damaging other parts of the brain. There is a diverse range of categories that fall under these tumors.

Glioblastoma is a type of brain cancer found in glial cells, cells in the brain that help support and maintain homeostasis, while meningioma is found in the protective layers of the brain and spinal cord.

What are common detecting methods?

Physical exam

The physician might check specific areas in search of lumps or clots underneath the skin. They might also look for a change in skin color or cyst formation as both would indicate a possible presence of a tumor.

Laboratory tests

Blood tests are usually used by doctors to detect any signs of cancer or abnormalities in the body. Common blood tests include Complete Blood Count (CBC) and blood protein testing; blood tests are usually used to identify leukemia and lymphoma.

Imaging tests

Imaging tests such as Positron emission tomography (PET) scan, Computerized Tomography (CT) scan, magnetic resonance imaging (MRI), and ultrasound, is used to see the location and characteristics of a tumor. This can help find the specific site of cancer.

Biopsy

A biopsy is a procedure that takes a sample of cells that make up the growth and runs tests to determine its formation. This can be done surgically or percutaneously. Biopsies can be essential to making a diagnosis and setting proper treatment for the patient.

What are some treatment methods?

Since the development and type of cancer are so unique to each patient, physicians use a variety of treatment methods to determine the most effective and personalized plan for each patient. Below are common treatments used to battle cancer.

Surgery

Surgery is an invasive procedure whose goal is to remove as much cancer as possible. Different types of surgeries have different aims. Diagnostic surgeries aim to find the origin and severity of cancer. On the other hand, removal surgeries aim to excise as much of the tumor as possible. Usually, physicians take a rim of extra tissue around it, called a margin, to make sure the tumor does not regrow. Furthermore, restorative surgeries can be a second practice to repair appearance or function due to past procedures.

Surgery is often the first step towards treatment.

Chemotherapy

Chemotherapy is a treatment that uses drugs, in the form of pills or injections, to fight cancer cells. These drugs cause damage to all cells, even healthy ones, but their full effect is only applied to cancerous cells, rapidly dividing cells. Some drugs such as alkylating agents are used to damage the DNA of the cell. Cancerous cells take in larger amounts of these agents because they are rapidly multiplying, causing their DNA to be damaged and cells to be destroyed.

This drug has a similar effect on healthy cells, specifically those that multiply often such as hair follicles and gastrointestinal lining. This is why symptoms of chemotherapy are hair loss and nausea. After the round of therapy is over, these damaged normal cells begin to renew and function as usual.

Radiation therapy

Radiation therapy uses high beams of energy from an external force, such as linear accelerators or cobalt machines, or internal force to target cancer cells.

Bone marrow transplant

Bone marrow transplant, also called stem cell transplant, is a transplant that replaced damaged bone and marrow with a new one given up from a donor. Bone marrow contains hematopoietic stem cells. By swapping out bone marrow that contains defective cells, the patient has new stem cells that can make healthy bone and bone marrow cells again. This type of transplant is common in patients with leukemia or lymphoma.

Immunotherapy

Immunotherapy is a cancer treatment that uses the patient’s immune system to fight cancer cells. It is usually used along with another treatment as it itself is not as powerful in defeating certain types of cancers. Immunotherapy can help the patient’s system to work harder and detect/fight cancer cells.

Targeted drug therapy

Targeted drug therapy uses drugs to specifically target cancer cells instead of affecting all the cells in the body like chemotherapy. The goal of arising targeted drugs is to turn off growth factors generated by cancer cells. This type of treatment is still relatively new, however, current research shows that it holds a lot of promise for the future.

What is hoped for in the next decade?

The past 10 years have brought a lot of advancement in cancer research. As a result of these discoveries, the fatality rate has decreased by more than 25% percent, and awareness, whether by the passage of laws or mandatory education upon these subjects in school, has been risen to eliminate or limit the usage of cancer-causing agents.

Scientists are working to increase the efficiency of these treatment methods as well as developing new ones that offer a different approach to this disease. One of the main struggles is how to keep normal cells healthy while killing defective cancer cells. Clinical trials that explore the use of CAR T-cell therapy, Monoclonal Antibodies, and genome profiling hold the potential to doing so.

Ethan Dmitrocky, an American Cancer Society professor and the director of Frederick National Laboratory for Cancer Research, among many others, holds an optimistic view on the future of cancer research.

Together, we will beat cancer!

Hi there! I am Andri, a super curious and passionate young researcher who loves biomedical and computer sciences. I love to read, write, and debate!