WHY CANCER RETURNS ?

  

We develop cancer cells inside our bodies every day. It’s an interesting fact that a power that fights with these cancer cells makes these deactivate and destroy every time. But why the disease cancer takes place when we all have the power to fight cancer cells? Why it becomes so dangerous that the patient dies? What are the types of cancer? How the cancer patients can be treated to put a full stop to this disease? Let’s discuss this.

img: google.com

WHAT IS CANCER?

The normal cells undergo a regulated division, differentiation, and apoptosis. The cell in the body grows and divides as part of their normal cell cycle. The genetic material i.e. DNA inside the cell’s nucleus contains the instructions to control this process. But when these functions of cells have deviated from the normal i.e. they lose control over their division, differentiation, and apoptosis, they become tumor cells. Sometimes the cells’ DNA becomes damaged. Normally DNA responds by either repairing itself or instructing the cell to die. But in cancer, the part of DNA that directs cell division becomes damaged. When these portions are damaged, DNA is unable to repair itself or cause the cell to die. Rather, the unrepaired DNA makes the cell develop and separate wildly into more harmed cells. A tumor forms as cancer cells multiply and displace the normal cells. As the tumor enlarges, it develops its own blood supply. So, it can be said that a tumor cell is the result of an abnormal proliferation of cells without differentiation and apoptosis. A tumor is said to be developed on solid tissue, but in cancer, the abnormal proliferation of cells occurs in any cell of the body.

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METASTASIS

Since cancer cells do not stick together as well as normal cells, they may break away and enter a new area of the body by the blood vessel. Cancer cells in a blood vessel may trouble other areas of your body and form additional tumors and this is called metastasis. Additional tumors may form in areas such as the lungs, liver, and bones. Another way cancer may spread to other areas of the body is through the lymphatic system. Cancer cells may enter lymph vessels near the tumor and travel to small glands called lymph nodes. If the cells pass through the nodes, they may continue to travel through the lymphatic system and form additional tumors.

(circulating cancer cell)

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TYPES OF TUMOR

The tumor may be of two types: Benign Tumor and Malignant Tumor. In a benign tumor, the neoplastic cells remain clustered together in a single mass and cannot spread to other sites. The great majority of primary tumors arising in humans are benign and are harmless. Neoplastic cells that do not remain localized and encapsulated and become progressively invasive and malignant are called Malignant Tumors. The term cancer refers specifically to malignant tumors.

According to the type of cells from which they arise, both benign and malignant tumors are classified, they are Epithelial, Mesenchymal, Hematopoietic, and Neuroectodermal. The most common human cancers are of the epithelial region – carcinomas. The non-epithelial malignant tumors include sarcomas, which originate from Mesenchymal cells; hematopoietic cancers, which arise from blood; and Neuroectodermal Tumors, which originate from the components of the nervous system.

Most of the cases of cancer are initiated by the genetic changes that occurred in the somatic cells, thus are not transmitted to the next generation. About 1% of all cancers are due to the genetic changes in the germinal cells and are therefore inherited. An interesting fact is about 80% of these inherited cancers are dominant in nature.

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THE PROCESS OF METASTASIS

The transition of a normal cell into a tumor cell is referred to as Transformation. The transition from a normal cell to a transformed state is a multistep process and is divided into 3 distinct stages: initiation, invasion, and progression. Initiation is a process in which the normal cells are changed to form the tumor cells. Progression is the stage in which the initiated cells are proliferated to increase the population of the initiated cells. Progression is the process of acquiring additional genetic changes leading to malignancy and metastasis of the changed cells.

CANCER CELLS AGAINST IMMUNITY

·         The cancer cells minimize the expression of the MHC-I molecules outside the cell for which, the macrophages, natural killer cells, cytotoxic killer cells, etc. of our body can’t detect the foreign particles as well. Thus the foreign particles can enter the body to develop cancerous activities.

·         Sometimes the macrophages that help the cells to present the carcinogenic cells on their surface through MHC-II molecules re-engulf the MHC-II molecule to alter the antigenic property for which, the cancerous cell can easily be activated without any interruption of antibodies inside the body.

·         Sometimes the cancerous cells minimize the expression of both the MHC-I and co-stimulatory B7 molecules for which the T-cell Receptor molecules along with CD28 molecules can’t recognize the cancerous cells and they easily get activated inside the body.

·         Sometimes the antibody masking property has a reverse effect on the body that provides good masking to the MHC molecules of the cancer cells and thus other killer cells can’t detect the carcinogenic cells for which those cells become active inside the body.

IMMUNITY AGAINST CANCER

An immune system is a group of specialized signaling molecules, cells, tissues, organs that work together to defend the body. These immune cells act against the cancer cells and deactivate these cells so that they will be discarded out and cancer will not occur in the body. Phagocytes, macrophages, natural killer cells, or cytotoxic killer cells and antibodies act against the cancerous cells inside the body and keep the body clean from cancer cells. The MHC-I molecules are very less on the cancer cell surface as compared to the normal cells. So these killer cells can detect them easily. Sometimes the lipid asymmetry can also help to detect cancerous cells. The phagocytic cells engulf the cancerous cells and dismantle the cancerous cells along with providing a signal to the immune system of the body to kill all the cancer cells with the help of antigen-presenting cells.

img: google.com

TREATMENT

The treatment of the cancer is by Chemotherapy, Radiotherapy, or Operation. In chemotherapy, certain chemicals or drugs are given to the patient so that the medicines will act upon the immune system to reactivate and act against the cancer cells and suppress the development of the tumor, and gradually dissolves the tumor cells. In radiotherapy, radiation is used to totally burn the cancer cells and make the disease stop. And in operation, doctors operate the tumor out of the body to stop the disease.

SO CANCER RETURNS

Doctors always prescribe for re-checkup of the patient for the confirmation of the deletion of cancer because as the cancer is a cellular level disease, it’s hard to confirm the complete deletion of the disease, because,  after the treatment, it’s not sure that the immune system is properly working against the cancer cells or not. As in the process of metastasis, the cancer cells travel to other areas of the body, thus, they can remain inactive with chemotherapy, but also can be expressed out with time. So it’s definitely very important to re-checkup that makes it confirm about it so that it will not return.

All the images are taken from Google.com.

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