What Is Cancer?

In biology, the cancer definition is as follows: a malignant growth caused by uncontrolled cell division. Normally, the cells grow and divide to provide new cells. These cells die when they are old enough, and new cells take their place. Abnormal cells are the opposite of normal cells. These abnormal cells are what can cause cancer. Cancer, also referred to as malignancy, is a disease characterized by an unusual development and uncontrolled growth of abnormal cells in the body. As the body is made up of a lot of cells, cancer can begin in almost any part of the human anatomy.

Cancer begins when the usual control mechanism of the body starts to malfunction and completely stops working. Instead of dying, the old cells grow out of control and culminate in forming new abnormal cells. These new abnormal cells divide uncontrollably, and they have the ability to get into and destroy the tissues of the body to form a mass of tissue. This mass of tissue is commonly known as a tumor. Although many cancers form tumors that are solid, there are also those that do not form tumors like cancers of the blood.

Just like what the name suggests, cancerous tumors are malignant. They can expand and reach the nearby tissues and also infect them. Moreover, as the tumors grow, some of these cells can separate or detach from the others and travel to other places in the body through the blood and lymph system. When these cancer cells do that, they can form new tumors far from the original tumor.

On the other hand, there are benign tumors, which, unlike malignant tumors, do not expand, reach, and infect other and nearby tissues. These benign tumors can be quite massive in size at times, but they do not grow back, unlike malignant tumors that have a chance of returning even when they are removed. Most benign tumors do not put lives at risk except for benign brain tumors, which can be dangerous and may lead to death.

Cancer Cells vs. Normal Cells

Normal cells and cancer cells are very different from each other. Normal cells become different types of distinct cells with their own functions. Cancer cells do not. Cancer cells divide continuously, completely unbothered by anything, and grow out of control and become invasive. The signals that are normally received and followed by normal cells, like signals about dividing and the planned life span or death of the cell, are entirely ignored by cancer cells.

Cancer cells are able to evade the body’s immune system, which protects the body from infections. They can go undetected by the immune system even though the immune system removes damaged and abnormal cells from the body. The immune system can also be used by existing tumors; they can use it to keep themselves alive and grow.

How Does Cancer Start in the Body?

Where does cancer come from? This is a common question asked when someone who cares for their health thinks of this disease. Everyone wants to know the cause of cancer so they can avoid it in hopes of saving themselves from cancer.

Cancer is a disease that deals with genetics as it is a result of alterations or changes in genes. These genes control the manner in which the cells in our body function, like growing and dividing. Such cancerous genetic alterations or changes can be inherited from the parents of the person.

How cancer starts can also be a result of all errors that happen when the cells divide, or it may be due to the damage of DNA. This damage can be because of specific exposures to environmental hazards or situations. Environmental exposures that often lead to cancer or cause cancer include being bare to substances like carcinogenic chemicals and radiation.

Cancer in each and every person has its own specific combination of genetic changes and factors, which continue to increase as cancer grows. For example, inside the same tumor, different genetic changes may occur in various cells.

Cell Division and Gene Mutation

There are times that a change will happen during cell division. This is called a mutation. Mutation means that there is a damaged or lost gene or a specific gene that is copied repeatedly. Cancer is caused by alterations or mutations to the DNA in the cells.

DNA has a lot of individual genes, and each gene contains directions or instructions on what functions the cell must do, including how to grow and divide. Errors can occur in these instructions, which hinders the normal function of the cell and give it the chance to be cancerous.

A gene mutation can instruct a normal cell to:

• Allow rapid growth. Gene mutation helps in fast cancer cell division and growth, producing many new cells that all have the same mutation.
• Keep uncontrolled cell growth. Healthy cells know when to stop growing as they reach a certain number for each type of cell. Cancer cells, however, lose this control that tells them when to stop growing.
• Make mistakes in DNA error repair. The repair genes in the DNA search for errors in the cell’s DNA and correct them appropriately. Mutation in a DNA repair gene can result in errors not being corrected anymore and further allowing cells to become cancerous.

These are the most common mutations in cancer. But there are many other gene mutations that contribute to causing cancer.

Mutations, in particular genes, can also mean:

• A cell starts making too many proteins that trigger cell division.
• A cell stops making proteins that are supposedly telling the cell to stop dividing.
• Abnormal proteins may be produced, which functions differently than the normal ones.

Risk Factors

Cancer can happen to anyone – whether they have any known risk factors or not. Still, it is better to have an idea of how cancer comes to the human body so one can be wary of the signs. Such factors that are known to increase a person’s risk of cancer include:

• Age – Most patients who are diagnosed with cancer are older people because it can take decades for cancer to develop. Even if it is common in older people, it is not an exclusive disease for adults, and people of any age can be diagnosed with it.
• Habits – Choices in an individual’s lifestyle can increase or decrease a person’s risk of cancer. Smoking, drinking, excessive sun exposure or frequent blistering sunburns, obesity, and even unsafe sex can contribute to cancer. Changing such habits can not only lower the risks of acquiring cancer but also keep the individual away from other illnesses.
• Family Background – Although there are instances when cancers are caused by an inherited condition, it only covers a small portion of risks. If cancer is common in the family, this means it is possible that genetic mutations are passed from generation to generation. But it is not always the case. Genetic testing is a good choice to know if a person inherited these mutations that might increase their risk of certain cancers. It is still important to remember that an inherited genetic mutation does not always mean a person will automatically get cancer.
• Environment – A person’s environment might contain harmful chemicals that can possibly increase their risk of cancer. For example, even if a person does not smoke, them inhaling secondhand smoke from those who do will still increase their risk. Chemicals in the workplace or even at home can also increase the risk of cancer.

Types of Cancer

How many types of cancer are there? There are many types of cancer – over a hundred. These types are commonly named from the tissues or organs the cancer is from. For instance, lung cancer starts in the cells of the lungs. Cancer can also be described by the type of cell that formed them.

Below are some of the main types of cancer.

Carcinoma

Carcinomas are the most common type of cancer. Carcinomas form and start in the epithelial tissues or cells which cover the surfaces of the body, both inside and outside – like the skin. Epithelial tissues also cover and line all organs in the body and the body cavities, like the inside of the chest.

There are various types of epithelial cells, and these can develop into different types of carcinoma. The different types of carcinoma include:

• Squamous Cell Carcinoma: This is a type of cancer that forms in the squamous cells. These are flat, surface-covering cells found in areas such as the skin or the lining of the throat. Squamous cells also line a number of other different organs, like the stomach, intestines, lungs, bladder, and kidneys. Squamous cell carcinomas are also referred to as epidermoid carcinomas.
• Adenocarcinoma: This is a type of cancer that forms and starts in epithelial cells that produce fluids or mucus. Tissues that have this type of epithelial cell are also called glandular tissues. Adenocarcinomas mostly include cancers of the breast, colon, and prostate.
• Transitional Cell Carcinoma: Transitional cells are cells that can stretch while an organ expands. Transitional cell carcinoma is a type of cancer that forms in a type of epithelial tissue called transitional epithelium, or urothelium. This tissue, which is composed of many layers of epithelial cells, is found in the linings of the bladder, ureters, part of the kidneys, and in a few other organs. Transitional cell carcinoma includes some cancers like cancers of the bladder, cancers of the ureters, and cancers of the kidneys.
• Basal Cell Carcinoma: This is a type of cancer that begins in the lower or basal layer of the epidermis, which is a person’s outer layer of skin. Basal cells line the deepest layer of skin cells.

Sarcoma

Sarcomas are a type of cancer that starts in connective tissues, which are the supporting tissues of the body. These tissues include bone and soft tissues like muscle, fat, blood vessels, lymph vessels, and fibrous tissue like tendons and ligaments that support organs.

Sarcomas are much less common than carcinomas. There are two main types:

• Bone Sarcomas: Osteosarcoma is the most common cancer of the bone.
• Soft Tissue Sarcomas: These are rare, but the most common types start in cartilage or muscle.

Leukemia

Leukemias, as they are cancers of the blood, are a type of cancer that begins in the blood-forming tissue of the bone marrow. Leukemias do not form or inhibits a solid form or solid tumors. Leukemia forms when the bone marrow makes too much white blood cells that are not fully formed and, therefore, do not work properly.

There is a large amount of abnormal white blood cells instead, which build up in the blood and the bone marrow, leaving no space for normal blood cells. With a low level of normal blood cells in the body, it is harder for the body to get oxygen to the tissues, control bleeding, and even fight infections.

Leukemia has four common types, which are categorized based on how quickly the disease gets worse: acute or chronic, and on what type of blood cell cancer starts in: lymphoblastic or myeloid. Leukemia is the most common type of cancer in children.

Lymphoma

Lymphoma is a type of cancer that starts in lymphocytes, which are disease-fighting white blood cells and are included in the immune system of the body. In lymphoma, abnormal lymphocytes build up in lymph nodes and lymph vessels, as well as in other organs of the body. The lymphatic system runs all throughout the whole body, so lymphoma can start anywhere.

There are two main types of lymphoma:

• Hodgkin lymphoma: People with this have abnormal lymphocytes or Reed-Sternberg cells. These cells usually form from B cells.
• Non-Hodgkin lymphoma: This is a large group of cancers that start in lymphocytes. The cancers can grow quickly or slowly and can form from B cells or T cells.

Myeloma

Myeloma is a type of cancer that begins in the plasma cells. Plasma cells are white blood cells that are made in the bone marrow. Plasma cells produce antibodies, also called immunoglobulins, which help fight infection. These cells can become abnormal and reproduce out of control, which results in a type of antibody that does not work properly in fighting infection.

Central Nervous System Cancers

Cancer can also start in the central nervous system of the body. It can form in the cells of the brain or the spinal cord. There are various types of brain and spinal cord tumors that are named based on what type of cell they were formed and where the tumor first formed.

The brain is made up of a lot of nerve cells called neurons and also contains special connective tissue cells called glial cells that support the nerve cells. The brain controls the body by sending electrical messages along the nerve fibers. The fibers run out of the brain and join together to make the spinal cord, which also takes messages from the body to the brain.

Brain tumors can be benign, which is not considered to be cancer. But it can also be malignant, which is, in other words, cancer. Tumors that start in the brain or spinal cord are not all cancerous; some are non-cancerous or benign and grow very slowly. Cancerous ones, on the other hand, tend to grow and spread. The most common type of brain tumor develops from the glial cells and is called a glioma.

Other Cancer Tumor Types

Germ Cell Tumors

Germ cell tumors are a type of tumor that starts in the cells that produce sperm or eggs and can occur almost anywhere in the body and can be either benign or malignant.

Neuroendocrine Tumors

Neuroendocrine tumors form from cells that release hormones into the blood, responding to a signal from the nervous system. These tumors, which may make more than the usual amounts of hormones, can cause many different symptoms and may be benign or malignant.

Signs and Symptoms of Cancer

Getting to know the possible signs and symptoms of cancer is an advantage to everyone as cancer can have anyone as its victim, no matter their age or what their health condition is. Although these signs are not enough to diagnose someone of cancer, it can serve as clues or guides in determining and finding the appropriate treatment for the problem. Any treatment works best when applied early, especially when a tumor is still small and has not spread anywhere else yet.

Having the following symptoms does not always mean someone has cancer. There are other common health conditions that can make a person experience such symptoms. It is best to see a doctor to be able to get a better and closer look at someone’s health and proceed with the appropriate actions.

Here are some common signs and symptoms of cancer for both men and women:

• Pain – There are types of cancer that hurt from the start. Brain tumors can also cause headaches, which last for some days, and do not get better even with the usual treatment. But at the same time, pain can also be a late sign of cancer, so seeing a doctor is best if the reason for the pain is unknown, and it won’t go away.
• Sudden and Unplanned Weight loss – Most people who have serious illnesses lose weight, and it is often one of the noticeable signs. In order to fight cancer, the body releases cytokines that result in weight and muscle loss and even a decrease or loss of appetite.
• Fatigue – Feeling tired all the time, but rest does not help? It is time to tell a doctor. Leukemia often exhausts a person out, or someone can have blood loss from colon or stomach cancer. Cancer-related weight loss can cause fatigue, too.
• Fever – A high fever that lasts for more than three days is a sign to call a doctor. There are cancers of the blood, like lymphoma, which cause a fever that lasts for days and even weeks.
• Changes in the Skin – Getting a checkup from a doctor regarding unusual and new moles, lumps, bumps, and marks on the body is important to make sure that you’re not already dealing with skin cancer. The skin can also provide clues to other types of cancers. For example, if the skin is darkened, looks yellow or red, itches, or sprouts more hair, or if there is an unexplained rash, it could be a sign of liver, ovarian, or kidney cancer, or even lymphoma.

Signs That the Cancer is Spreading

Cancer is a serious disease because it has the ability to spread in different parts of the body, and the patient may not even be aware of it. But how does cancer spread?

The spreading of cancer cells is called metastasis. Metastatic cancer will have the same name as the first or primary cancer in the body. For example, breast cancer, which spreads to the lungs, is called metastatic cancer and is considered to be stage IV breast cancer instead of lung cancer.

As metastatic cancer does not show or cause symptoms all the time, if symptoms ever occur, its characteristic and frequency depend on the tumor’s size and location. Here are a few common signs of cancer spreading, also called metastatic cancer:

• Pain and fractures – it has spread to the bone.
• Headache, seizures, or dizziness — it has spread to the brain.
• Shortness of breath — it has spread to the lung.
• Jaundice or swelling in the belly — it has spread to the liver.

Treatment of Cancer: An Overview

As cancer has been around for a long time, there have also been different treatments and cures available for it. The specific treatment option will depend on what type of cancer the patient has, the stage, whether it has spread to other parts of the body, and the patient’s general health. The main goal and aim of treatment are to eliminate all cancerous cells while preventing inducing damage to nearby normal cells at the same time. Modern and advanced technology makes such treatments possible and attainable.

There are three main treatments, namely:

• Surgery – where the tumor is directly removed
• Chemotherapy – where cancer cells are killed with the use of chemicals
• Radiation therapy – where X-rays are used in eliminating cancer cells

Currently, researchers are still trying to discover all the subtypes of cancer, which requires different treatment approaches for each of them.