Cancer is one of the most common diseases that prevails on the planet Earth among human beings. Every year millions are diagnosed with cancer as well as millions of people die due to cancer across the globe. It is surely one of the deadly diseases which is known to humankind. But how to explain it to a common man? What Is Cancer? Well cancer is defined as the uncontrolled multiplication of one’s body cells which may or may not spread to other parts of the body.
Cell multiplication is a normal process which occurs in every living human body as the body needs new cells to replace the worn and torn out cells. But in diseases like cancer this normal process of cell division/multiplication becomes abnormal and the result is uncontrolled proliferation of cells. Most people use term tumors as cancer and vice versa but in scientific terms a tumor is an abnormal mass of tissue that is formed when cells start growing more than required or old cells don’t die and new cells keep adding up in that tissue. Tumors can be benign or malignant. It is a malignant tumor which is cancerous in nature. That means every tumor is not cancer. Benign tumor doesn’t spread to different parts of the body. It just infiltrates the nearby area.
Types Of Cancer
As we just defined that What is Cancer? Now, let’s also try to study types of cancer. There are over 100 types of cancer recognized till now. There are different types of cancer which are classified on the basis of its origin, that means that where growth of cancerous cells begins in the body, and they are as follows:
1. Carcinomas – this type of cancer can be defined as the cancer which begins in the skin or the tissue which lines the internal organs and glands of the body , that is the Epithelial tissue. This type of cancer forms solid tumors in many cases.
The carcinomas are further classified as:
|No.||Type Of Epithelial Tissue||Common |
|1||Adenocarcinoma: In this type of carcinoma the epithelial tissue usually secretes fluid or mucus, therefore referred to as glandular tissues.||Breast Cancer,|
|2||Basal cell Carcinoma: In this carcinoma the cancerous growth begins in the base of the epithelial tissue, which is the outer layer of the skin.||Skin cancer|
|3||Squamous Cell Carcinoma: In this carcinoma the squamous cells are involved which is present in the lining of many organs like stomach, intestines, lungs, bladder, kidneys etc. It is also known as Epidermoid Carcinomas.||Lung Cancer, Urinary Bladder Cancer|
|4||Transitional Cell Carcinoma: This type of cancer occurs in the Transitional epithelium/Urothelium. This tissue consists of many layers of epithelial tissue commonly found in bladder, uterus kidneys etc.||Uterine Cancer, Kidney Cancer,|
2. Sarcomas – sarcomas can be defined as the cancer which forms in bone and soft tissues like fat, muscles, blood vessels, lymph vessels, tendons, ligaments etc.
The most common example of sarcoma is osteosarcoma. The common soft tissue sarcoma includes liposarcoma, Kaposi sarcoma, leiomyosarcoma etc.
3. Leukemias – this cancer is referred to the blood forming tissue in our body which is known as the bone marrow. In this cancer there is no formation of solid tumors. The white blood cells (WBCs) start proliferating abnormally this leads to less number of normal blood cells like RBCs (Red Blood Cells). As the RBC count starts falling in the bloodstream the oxygen carrying capacity decreases in the whole body. Leukemia can be Acute or Chronic ( this classification is based on the progression speed of the cancer) or it can be Lymphoblastic or Myeloid (this classification is based on the typeof blood cells that becomes cancerous).
4. Lymphomas – this cancer occurs in the Lymphocytes ( T-cells or B-cells ). T-cells and B-cells are types of blood cells which are an integral part of our immune system. There are two main kind of lymphomas : Hodgkin lymphoma (only involve B-cells ) and Non-Hodgkin lymphoma (may occur in B-cells or T-cells)
What Causes Cancer?
Till now we have learned What is cancer ? and types of cancer ? But one integral question which remains unanswered is What causes cancer ? Well there are many factors which give rise to cancer. The causes of cancer can be broadly divided into three groups, they are as follows:
1. Genetic Factors
The genetic factors or also known as Hereditary factors are one of the causes of the cancers. There are more than 50 types of hereditary cancer known till now. But only 0.3% of people are carriers of hereditary cancers. Genetic factors include the mutation in one or more genes and this predisposes the affected person to development of cancers and its early onset too. The gene mutation is of two types : one is Germline [in this the mutation is carried over the generations] or Somatic [in this the mutation happens in body cells beside the gametes].
Some common hereditary cancer syndromes are :
- Werner Syndrome
- Bloom Syndrome
- Fanconi Anemia
- Xeroderma Pigmentosum
2. Environmental Factors
This includes external factors [Chemical and Physical Agents] which when introduced into the body via different means can lead to the development of cancer over a period of time. These agents are known as Carcinogens.
Some of the most common carcinogen includes :
- Nicotine (Smoking)
- Radiations ( ionizing and non ionizing radiations) like UV rays, x-rays, gamma rays, infrared radiations, microwave etc
3. Constitutional And Lifestyle Factors
Well not only genetics , substances are the causes of cancer. Any person’s lifestyle and constitution also plays a vital role in the development of cancer. Today diet and Obesity accounts for 30% cases of cancer deaths around the world. Cancer related to obesity includes colorectal cancer, thyroid cancer, kidney cancer, esophageal cancer, endometrial cancer etc. Lifestyle factors include substance abuse, lack of physical activities, alcohol, smoking etc.
Some of the rare causes of cancer includes —
- Organ Transplants: main cause is undetected malignant melanoma during the process of organ harvesting. Another example is kaposki’s sarcoma.
- Maternal-foetal Transmission: this is one of the rare cause of cancer and usually seen in cares of acute leukaemia, lymphoma, melanoma and carcinoma from mother to fetus has been seen.
- Trauma: well physical injuries or trauma leading to cancer is pretty rare . I5 is not directly the cause of the cancer but when combined with other factors like excessive exposure to heat to a particular organ due to work or other health issue may rise to skin/epithelial tissue cancer.
Well knowing What is cancer ? It’s types and causes in one article is impossible to achieve . We have a brief outline which tells what is cancer? All cancer are not as life threatening and can be reversed too if detected at the early stage of the disease. This can be done by the diagnosis and prognosis of the cancer. The correct treatment of cancer is completely dependent on its findings and it’s stage. Therefore cancer screening is a must especially for people who have a genetic tendency of the deadly disease . Some of the cancer are preventable by changes in lifestyle too. So we to overcome the disease we need to work from the basic cause, as not one factor is responsible for a disease like cancer.