Cancer
Cancer is the name of crab which is used as a symbol to denote the disease. The study of cancer is called 'Oncology'. The cancer is unregulated and uncontrolled proliferation of cells or it is breakdown of regularity mechanism that governs normal cell division. The tumor or neoplasm formed by uncontroll
ed cell division can be of 2-types.a. Benign Tumors b. Malignant Tumors a. Benign Tumors- They are localized tumors and are bound within a connectivity tissues coating. They do not spread over the surrounding tissues. They are not fatal or harmful E.g. Moles and warts.
b. Malignant Tumors
They are cancerous of harmful and spread into surrounding tissues by 2-means-invasion and Metastasis.
Invasion is the penetration of the cells of malignant tumor into the neighboring tissue where they form invasion tumors.
Metastasis is the penetration of the cells of into the blood capillaries form where they are carried to different parts of the body.
Types of cancer
1. Carcinoma 2. Sarcoma 3. Leukemia
Carcinoma- It is the cancer of epithelial lining, which can be ectodermic, mesoderm in origin. This
type of cancer can develop in the gut living, glands (exocrine or endocrine) or skin etc. About 80% of the cancers are carcinomas. E.g. Lung cancer, breast cancer, colon cancer, skin cancer, cervix cancer etc.
Sarcoma- it is the cancer of connective tissues of muscles, and is mesoderm in organic. Only 1-2%of the cancers are of this type. e.g. cancer of bone and cartilage.
Leukemia- It is the cancer of blood particularly of granulocytes. (WBCS), an
d is so called Granulocytic Leukemia. It is related to the 22nd chromosome (auto some), the philadedelphia chromosome.The above three are the major categories of cancer. The other sub categories can be-
i. Lipoma- It is the cancer of adipose tissue.
ii. Lymphoma- It is the cancer of lymphatic tissue/lymphocytes. The most common lymphoma is Hodgkin's disease.
iv. Teratoma- It is the cancer of embryonic or fetal tissue. It is a tumor like embryo like tumor.
v. Myeloma- It is the cancer of bone marrow.
vi. Myoma- It is the cancer of muscles.
Causes of Cancer
The cancer causing agents of factors (physical or chemical) are called Carcinogens.
1. Physical agents (Radiations)
UV rays, X-rays, infra-red or Gama-rays can cause gene mutation and produce oncogenic transformation. The cancer can also develop due to radiation of nuclear bomb.
2. Biological agents (Virus)
Virus do not cause cancer as pathogens but alter DNA- sequence which produces abnormal proteins. The viruses are called oncovirus which do not cause cancer but can be their causes.
3. Chemical agents-
Certain chemicals may cause cancer e.g. n-nitroso-di-methylene (in cigarette smoke) and Asbestos dust for lung cancer. Cadmium oxide for cancer of prostate gland; PVC (Polyvinyl chloride) and Alfa toxin (from fungus, Aspergilla) for cancer of liver. Nitrosamine for colon cancer, and diethylstilbestrol for vaginal v. Myeloma- It is the cancer of bone marrow.
vi. Myoma- It is the cancer of muscles.
Causes of Cancer
The cancer causing agents of factors (physical or chemical) are called Carcinogens.
1. Physical agents (Radiations)
UV rays, X-rays, infra-red or Gama-rays can cause gene mutation and produce oncogenic transformation. The cancer can also develop due to radiation of nuclear bomb.
2. Biological agents (Virus)
Virus do not cause cancer as pathogens but alter DNA- sequence which produces abnormal proteins. The viruses are called oncovirus which do not cause cancer but can be their causes.
3. Chemical agents-
cancer etc. Carcinogens can also be categorized on the basis of their mode of action as-1. DNA –Transformers – These agents can cause alternation in DNA that leads to cancer.
2. Tumor- promoters –These agents (e.g. Growth factor or hormones) promote the proliferation of cells which have already undergone genetic alternation.
3. Tumor-Virus – Such viruses are capable of making oncogenic transformations.
Prevention of Cancer
1. Vitamin supplements- Vitamin-A prevents carcinoma; vitamin-E, an anti-oxidant, Vitamin-C and vitamin-B17 are also anti-cancer.
2. Roughage-Fiber-rich food stimulates peristalsis and prevents gut cancer (particularly of colon).
3. Low-calorie diet –Reduction in calorie intake prevents the occurrence of cancer.
Symptoms (warning signs)
1. In colon cancer the nature of stool keeps changing with unexplained weight loss.
2. In breast cancer there can be lump on node indicating the presence of cancer of tumor.
3. In case of wart or mole the nature of tissues from time to time.
4. In case of throat cancer there in persistent hoarseness and coughing.
5. Pap smear test- It is the test for cervical cancer. The epithelial lining of cervix (neck of uterus) is taken out for biopsy. The malignant cells show overlapping and have abnormal nuclei.
1. On the basis of blood or biopsy (remember, that the histological test after death of the organism is called autopsy).
2. X-ray studies.
3. CT-scan or MRI for internal organs, like pancreas, liver, gall bladder etc.
4. By using monoclonal antibodies (called magic bullets).
5. The cancer causing genes called oncogenes, are present in the normal cells but they remain suppressed.
6. According to some oncologists the photo-oncogens in the present in normal cells but they change into oncogens in the presence of carcinogens.
7. Still others believe that the cancer develops due to suppression of antioncogenes present in the normal cells.
8. However the cancer associated genes can be divided into three categories.
i. Genes including cell proliferation
ii. Genes inhabiting cell proliferation
iii. Genes regulating programmed cell-death. The alternation (mutations) in any of the above category of genes causes cancer.
Treatment
1. Surgery
It is used for localized cancer of larynx, uterus, breast etc. The disadvantage of the surgery is the recurrence of malignancy due to the cells left-out. The layers can also be used for killing of surgically removing the malignant tissue.
2. Radiations
The ??radiations can be used to kill the cancerous cells. The disadvantage of this technique is that some of the neighboring cells (non-cancerous) can be damaged.
3. Chemotherapy
Two types of chemicals can be used to treat the cancer if the metastasis has already set in. They can either mimic the chemicals which prevent DNA republication, or prevent translation of the proteins. As the cell division is stopped the growth of secondary tumor does not occur. The problem with chemotherapy is that the cell division of normal cell is also affected and some side-effects, like nausea, hair fall etc, do occur.
4. Grafting or transplantation
In the case of Myeloma, the cancer of home marrow, the marrow can be transplanted from a donor to the cancer patient.
5. In certain type of cancers, the immunotherapy, use of monoclonal antibodies, can be very effective.
2. Tumor- promoters –These agents (e.g. Growth factor or hormones) promote the proliferation of cells which have already undergone genetic alternation.
3. Tumor-Virus – Such viruses are capable of making oncogenic transformations.
Prevention of Cancer
1. Vitamin supplements- Vitamin-A prevents carcinoma; vitamin-E, an anti-oxidant, Vitamin-C and vitamin-B17 are also anti-cancer.
2. Roughage-Fiber-rich food stimulates peristalsis and prevents gut cancer (particularly of colon).
3. Low-calorie diet –Reduction in calorie intake prevents the occurrence of cancer.
Symptoms (warning signs)
1. In colon cancer the nature of stool keeps changing with unexplained weight loss.
2. In breast cancer there can be lump on node indicating the presence of cancer of tumor.
3. In case of wart or mole the nature of tissues from time to time.
4. In case of throat cancer there in persistent hoarseness and coughing.
5. Pap smear test- It is the test for cervical cancer. The epithelial lining of cervix (neck of uterus) is taken out for biopsy. The malignant cells show overlapping and have abnormal nuclei.
1. On the basis of blood or biopsy (remember, that the histological test after death of the organism is called autopsy).
2. X-ray studies.
3. CT-scan or MRI for internal organs, like pancreas, liver, gall bladder etc.
4. By using monoclonal antibodies (called magic bullets).
5. The cancer causing genes called oncogenes, are present in the normal cells but they remain suppressed.
6. According to some oncologists the photo-oncogens in the present in normal cells but they change into oncogens in the presence of carcinogens.
7. Still others believe that the cancer develops due to suppression of antioncogenes present in the normal cells.
8. However the cancer associated genes can be divided into three categories.
i. Genes including cell proliferation
ii. Genes inhabiting cell proliferation
iii. Genes regulating programmed cell-death. The alternation (mutations) in any of the above category of genes causes cancer.
Treatment
1. Surgery
It is used for localized cancer of larynx, uterus, breast etc. The disadvantage of the surgery is the recurrence of malignancy due to the cells left-out. The layers can also be used for killing of surgically removing the malignant tissue.
2. Radiations
The ??radiations can be used to kill the cancerous cells. The disadvantage of this technique is that some of the neighboring cells (non-cancerous) can be damaged.
3. Chemotherapy
Two types of chemicals can be used to treat the cancer if the metastasis has already set in. They can either mimic the chemicals which prevent DNA republication, or prevent translation of the proteins. As the cell division is stopped the growth of secondary tumor does not occur. The problem with chemotherapy is that the cell division of normal cell is also affected and some side-effects, like nausea, hair fall etc, do occur.
4. Grafting or transplantation
In the case of Myeloma, the cancer of home marrow, the marrow can be transplanted from a donor to the cancer patient.
5. In certain type of cancers, the immunotherapy, use of monoclonal antibodies, can be very effective.
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