Difference between Tumors and Cancers
A tumor is one of the ailments that develop in a human body without the involvement of any pathogens. It is an abnormality that occurs in a tissue of an organ due to the uncontrolled growth of cells. In this section, we will study the definition, meaning, and anatomy of tumors elaborately. We will also discuss the different stages of tumors diagnosed and their connection with the formation of cancer.
What is a Tumor Definition?
Tumors, also known as tumor cells, are caused by the uncontrolled and abnormal growth of the cells in an organ, skin, or membrane. The cells were functional and normal in the beginning. Due to certain changes in the genetic material, the normal cell division process aggravates in an abnormal way resulting in the division of cells uncontrollably. This uncontrolled division of cells causes swelling in the tissue causing a tumor.
The pre-existing cells in the tissue do not perform the same functions, before resulting in the formation of a tumor. A tumor can cross the barrier due to its growth and can affect the surrounding tissues. The growth is generally unrestrained. As per the tumor definition, the swelling is different from that of inflammation. It is also called neoplasm. The appearance of the tumor cells is absolutely different from that of the normal cells, showing the presence of cancerous growth.
A tumor has three different stages. These stages are defined based on the characteristics of the cells and tissues. The prime factor that decides the stages of a tumor is called metastasis. Metastasis means the degree or tendency of spreading a tumor.
Tumor Stages
Here is a Brief Description of the Tumor Stages:
1. Benign Tumor
This type of tumor is small in size and can be found at a particular site. It has not spread in the other parts of the body which means the growth is still restrained within the barriers of a tissue. The location can define the fatality of a tumor. If it is in the brain, it can interfere with the normal functioning of a patient and can be very fatal. The treatment of this type of tumor involves invasive procedures such as surgery.
2. Malignant tumor
If we define a tumor at this stage, it will have crossed the tissue barriers and is about to spread. These tumors are cancerous in nature and the cells can pass through the bloodstream to affect other tissues and organs. In this stage, the tumor has reached the metastatic stage and causes the formation of secondary tumors in different parts of the human body.
3. Premalignant Tumor
This is an intermediate stage of the tumors where they are benign but shows malignant features. It means that this tumor is about to break out of the shell and release neoplastic cells into the bloodstream. It shows the hidden potential to become a cancerous tissue and increase the risk of malignancy.
Now that you have understood the neoplasm's meaning and the difference between the three different types of tumors, let us proceed to understand the reasons for the formation of tumors. It can be caused due to chemical exposure such as tobacco, smoking, and occupational hazards. It can happen due to radiation. It can also happen due to biological factors such as heredity, viral oncogenes, etc.
Diagnosis of Tumors
After analyzing the tumor's meaning, you can conclude that it is an abnormal growth of the tissue cells. It can be diagnosed by doctors without the use of any medical equipment. Certain tumors that are close to the periphery or skin can be felt. The abnormal growth can be detected by the patient alone.
When something anomalous or symptoms are detected, tests are done based on the location of a tumor. Most tests begin with imaging ones to confirm the location of a tumor. The diagnosis of different types of tumors depends on the location, stage, and other ailments a patient is suffering.
If it is a cancer tumor, the next diagnostic procedure is conducted. To understand the stage of cancer, the following tests are done methodically.
The abnormal tissue cells are collected to understand the level of malignancy and metastasis.
The cells are then sent to the labs for histopathological studies. In this step, a series of tests are done to understand the malignant level of the cells.
The other tests involve radiography tests. These tests reveal whether any tumor or cancerous growth is present in any other part of the human body.
Computed tomography is also a non-invasive imaging technique where deep scans are done to find out any anomalous growth in the body.
The ultimate level of diagnosing cancer is by performing molecular biology testing techniques.
Treatment of Tumors and Cancers
As mentioned earlier, the treatment plan is hatched based on the position, stage, and malignancy level of the tumors and cancers. The demographic features and other ailments of a patient are also considered. Tumors are generally surgically removed from the location. The abnormal tissue is marked and then removed.
When the tumor has become malignant, radiation therapy is proposed. It can also be done after the surgical removal of the abnormal growth. Once the tissues are removed, tests are done to find out the malignancy level. If the doctors think that it might have spread in other regions, they will go for radiotherapy or chemotherapy. Chemotherapy is the process where anticancer drugs are pushed to the circulatory system to make every cell of the human body free from the threat.
FAQs on Tumor
1. What is a tumor as defined in the CBSE Biology syllabus?
A tumor, also known as a neoplasm, is an abnormal mass of tissue that results from uncontrolled cell division. In a healthy body, normal cells possess a property called contact inhibition, which stops their growth upon contacting other cells. When cells lose this property, they divide excessively, leading to the formation of a tumor.
2. What is the main difference between a benign tumor and a malignant tumor?
The primary difference lies in their growth pattern and ability to spread.
- A benign tumor remains confined to its original location and does not invade surrounding tissues. It is generally non-cancerous and can often be removed surgically.
- A malignant tumor is cancerous and invasive. Its cells can break away, travel through the blood or lymph systems, and form new tumors in other parts of the body. This dangerous property of spreading is called metastasis.
3. What are the major types of carcinogens that can cause a tumor to form?
Carcinogens are agents that can trigger the transformation of normal cells into cancerous cells, leading to tumor formation. According to the NCERT curriculum, they are categorized as:
- Physical Agents: Includes ionizing radiations like X-rays and gamma rays, and non-ionizing radiation like UV rays.
- Chemical Agents: A prominent example is the nicotine found in tobacco smoke, which is a major cause of lung cancer.
- Biological Agents: Certain viruses, known as oncogenic viruses, can cause cancer. These viruses contain genes called viral oncogenes.
4. Why is the loss of 'contact inhibition' considered a critical event in tumor development?
Contact inhibition is a fundamental regulatory mechanism that signals normal cells to stop dividing once they form a complete layer and touch each other. This ensures tissues grow in a controlled and organised manner. The loss of this property is a critical hallmark of cancer because, without this 'stop' signal, cells continue to proliferate uncontrollably. They pile up on one another, forming the disorganized cell mass characteristic of a tumor. This breakdown in cell-to-cell communication is a key reason for the abnormal growth seen in cancer.
5. How does the concept of cellular oncogenes explain the origin of some tumors?
Normal cells contain specific genes called cellular oncogenes (c-onc) or proto-oncogenes. These genes play essential roles in regulating normal cell growth and differentiation. However, when these proto-oncogenes are activated or mutated under certain conditions—such as exposure to carcinogens—they can transform into active oncogenes. This activation leads to the loss of regulatory control over the cell cycle, causing the cell to undergo uncontrolled division and eventually form a tumor.
6. Why is a biopsy important for diagnosing the nature of a tumor?
A biopsy is a crucial diagnostic tool because it provides a definitive answer to whether a tumor is benign or malignant. During a biopsy, a small piece of the suspected tumor tissue is removed and examined under a microscope in a process called histopathological study. This examination reveals the characteristics of the cells, such as their structure, arrangement, and rate of division. This information is vital for determining the correct diagnosis, predicting the tumor's behaviour, and planning the most effective treatment strategy.
