NON _ COMMUNICABLE DISEASES ( NCDs)


Why in Non_ Communicable Diseases?

A recent WHO report " Invisible numbers _ the true scale of non_ communicable diseases " started that non_ Communicable diseases led to 66% of deaths in India in 2019.Ministry of Health and Family Welfare (MoHFW)released Strategic Operational Guidelines for National Programme for Prevention & Control of Non-Communicable Diseases (NP-NCD) 2023-203 for the management of non-communicable diseases in India. 

 Non_ Communicable diseases:

Non_ Communicable diseases  also known as chronic diseases, tend to be of long duration and are the result of a combination of genetic, physiological, environmental, and behavioral factors. 

■ Main types of NCDs are cardiovascular disease(like heart attacks and stroke), cancers, chronic respiratory disease(such as chronic obstructive pulmonary disease and asthma) and diabetes. 

■ NCDs contribute to around 71% of all the deaths globally and to about 60% of all deaths in india.

NON _ COMMUNICABLE DISEASES 

The non communicable disease remained confined to the persons who suffer from them. 

1):Diabetes mellitus:

It exists  in two forms ; Insulin _ dependent. The insulin _ dependent form is caused by a failure of  the B_ cells to produce adequate  amounts  of insulin; the non_ insulin _ dependent form appears to involve failure  of insulin to facilitate the movement of glucose into cells. In both disorders the blood glucose concentration is elevated above the normal range. Excessive concentration of glucose in the blood is called hyperglycemia. Some of the glucose is excreted in the urine, and water follows the glucose, causing excessive urination  and dehydration of body tissue. Insulin _ dependent diabetes is the more severe form of disease. It requires insulin for treatment. Non_ insulin _ dependent diabetes appears relatively late in life and can  often be controlled by limiting carbohydrates in the diet or by the use of oral hypoglycemics ( drugs that apparently  stimulate  the action of insulin). A tendency  toward non_ insulin _ dependent diabetes appears to he inherited as an autosomal recessive characteristic 

2. Cardiovascular diseases  : 

The diseases that affect the blood vessels and the heart are called cardiovascular diseases.

 

(i) Artiosclerosis :

Hardening and loss of elasticity of the arteries is commonly referred to as arteriosclerosis. It causes hypertension ( high blood pressure).

(ii) Atherosclerosis: In this disease a lumpy thickness develops on the inner wall of the arteries that prevents the dilation of vessels ( arteries). The vessels become smaller in diameter and cannot fully expand .It is considered that a variety of dietary sodium is  sometimes restricted.

(iii) Hypertension (High blood pressure).It is defined  as a resting arterial pressure exceeding 120/ 80 over a prolonged  period of time. Disorders that can result from untreated hypertension include heart failure, kidney damage and cerebro__ vascular accident ( rupture of a cerebral artery sometimes caused a stroke). Treatment generally  involves the use of drugs that inhibits the action of the sympathetic nervous system. Dietary sodium is sometimes restricted. 

(iv) Coronary Heart Diseases: The coronary arteries, supply blood to the muscles of the heart.They supply oxygen and nutrients to the heart and carry carbon dioxide and other metabolic wastes  from the wall of the heart. Coronary heart diseases include angina Pectoris and coronary thrombosis, 

(a) Angina Pectoris. Sclerosis of the coronary arteries can cause " pain in the chest". This anginal pain usually starts in the centre of the chest and spreads down the left arm. 
(b) Coronary Thrombosis or Myocardial Infarction (MI) : A clot may form in the lumen of a coronary artery, it is  called coronary thrombosis. Therefore, a large portion of the heart muscle is deprived of blood and the patient develop a "heart attack ".Anticoagulant treatment helps to prevent the formation and  extension of blood clots.

(v) Rheumatic Heart  Disease (RHD) : This  is the more frequent cardiovascular disease in India below the age of 20 years. Thus childhood throat infection should be taken seriously. The patient may have an acute rheumatic fever,  joint pains and infection of throat. Rheumatic fever may cause permanent damage of one or more values ( mitral or aortic semilunar values), pericarditis and myocarditis. Streptococcus (bacteria) causes RHD.Coxsackie B_ 4 _ virus has been suggested as a conditioning agent.  The risk of acute rheumatic fever is greatest where there is bad housing, overcrowding end inadequate conditions of hygiene. 

3. Stroke ( Cerebrovascular Accident or CVA: 

It is the sudden interruption of blood flow to a portion of the brain because of block or rupture of a cerebral blood vessel. Thus the brain cells do not get oxygen and glucose. This can cause paralysis, loss of speech, etc.

 4 .Artritis or Aching  Joints:

Some important types of arthritis are as follows: 
(i) Rheumatoid arthritis: It is the most common arthritis disease. Rheumatoid arthritis is an inflammation of the synovial membrane in synovial joints. When this membrane, which is the source of synovial fluid, becomes inflamed, it produces too much fluid. The joints swell and become extremely painful. In response to the inflammation and swelling, a hard tissue forms over the cartilage articulations. This tissue makes the joint stiff. Movement then becomes more painful. In  a course of time, the new tissue can grind away the entire cartilage. When this happens, the two bones fuse and the joint becomes totally immovable. A kind of rheumatoid arthritis that occurs in younger people is Still's disease.
 (ii) Osteoarthritis : It affects only the cartilage at synovial joints. The cartilage erodes and new bone is deposited in lumps. The lumps  make movement difficult and finally  impossible. Many people  who suffer thi form of arthritis have no pain, bit their fingers  may curl and permanently arch and their wrists and other joints may display lumps of bone  formation.

(iii) Gout : To there is the accumulation of uric crystals in synovial  joints. The accumulation makes movement both difficult and painful.Iric acid, a byproduct of protein metabolism is normally excreted  in the urine. Gout sufferers should avoid meat, particularly  liver, kidney, brain, thvmus gland, and other glands. 


 Non _ Communicable Diseases ( NCDs): 

● NCDs, also known as chronic diseases, tends to be of long duration and are the result of a combination of genetic, physiological, environmental and behaviours factors. 

● NCDs  are not transmitted from person to person. These diseases persist for a long time and are generally slow to progress.

● NCDs often affect people during their most productive years. When individuals with NCDs face tremendous healthcare costs and a restricted ability to work, households struggle with increased financial risk.

Covid _ 19 highlighted the links between  NCDs and infectious diseases, with serious impacts on NCD care.

■ In the early months of the pandemic, 75 percent of countries reported disruption to essential NCD services.
● Guidelines were released on the occasion of World Hypertension Day and as a part of a G20 co-branded event.
● Key Highlights of the Guidelines
■Focus on primary and secondary prevention clinical support for NCDs.
■The existing National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS) programme has been renamed National Programme for Prevention & Control of Non-Communicable Diseases (NP-NCD).
☆Also, widening the ambit of theprogramme by including Chronic Obstructive Pulmonary Disease (COPD) and Asthma, Non-Alcoholic Fatty Liver Disease (NAFLD), Pradhan Mantri National Dialysis Programme (PMNDP) etc.
■Comprehensive Primary Healthcare Non-
Communicable Disease (CPHC NCD IT) portal renamed as National NCD Portal.
☆ Portal enables population enumeration, risk assessment, and screening for five 
common NCDs.





Other Initiatives launched during event 

● 75/25 initiative launched: 75 million people with hypertension and diabetes to be put on Standard Care by 2025, through the PHCs.
 ■ It is the largest cover of NCDs in the world for primary healthcare. 
●Shashakt Portal was launched for training of 40,000 Primary Health Care Medical Officers on Standard Treatment Workflow for NCDs initiated to realize health care services closer to the community.

Measures taken by India to prevent NCDs:

National Programme for Prevention and control of cancer, Diabetes, Cardiovascular Disease and Stroke ( NPCDCS).

preventive aspects of NCDs is strengthened under  Comprehensive Primary Health Care through Ayushman Bharat Health Wellness Centre scheme.

Food safety  and Standards Authority of India ( FSSAI) has banned sales and advertisements of junk foods in school canteens and within 50 metres around school campuses.

FSSAI has launched 'Eat Right India'movement to improve public health and combat negative nutritional trends to fight lifestyle diseases. 

■ It also launched a mass media campaign'Heart Atrack Rewind'  for the elimination of industrially produced trans_ fat in the food supply.

 Pradhan Mantri Ujjwala Yojana helps to reduce indoor air pollution. 

● In response to WHO's Global action plan for the prevention and control of  NCDs 2013 _ 2020, India is the first country to develop specific national targets to reduce number of  global premature deaths from NCDs by 25% by 2025.

 Promotion of an active life through activities like Yoga which can address the risk of cardiovascular diseases.

Challenges in handling NCDs in India:

 ● Lack of trained human resources: As per the Ministry of Health and Family Welfare country had only one doctor for every 1,457 people, although WHO recommends a doctor patient ratio of 1:1000. 
●Low budget allocation and utilisation: For example, Union Budget 2023-24, budget has cut funding for non-communicable disease control programmes to Rs 289 crore from last year’s outlay of Rs 500 crore.
 ● Poor implementation plans: Such as lack of comprehensive information pool and management information system to  efficiently monitor the reach and implementation progress of the national NCD programme. 
● Poor adherence to medications: For example -one in two patients do not take their treatments as directed, and onethird of patients who take medicines stop their treatments earlier than directed. 
● Changing Lifestyle: Due to sedentary lifestyle in urban areas and it is driven by unchallenged aggressive marketing strategies of unhealthy foods and beverages and alcohol industry. 

 Initiatives taken by India to curb NCDs 

● National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS) Programme: It was launched in 2010 by Ministry of Health and Family Welfare was launched under the National Health Mission (NHM). 
■ Programme is being implemented to address common NCDs like Cardiovascular Diseases, hypertension, etc. 
●National Action Plan: By Ministry of Health and Family Welfare launched in response to the “WHO Global Action Plan for the Prevention and Control of NCDs 2013-2020”. ■ Aimed at reducing the number of global premature deaths from NCDs by 25% by 2025.
 ●Preventive Steps: This aspect of NCDs is strengthened under Comprehensive Primary Health Care through Ayushman Bharat Health Wellness Centre scheme, by promotion of wellness activities and targeted communication at the community level. 
● Healthy Diet: Healthy eating is also promoted through Food Safety and Standards Authority of India (FSSAI) through Eat Right India movement, which will help to develop healthy dietary plan and hence reduces chance of NCDs. 
●Physical Activity: Fit India movement is implemented by Ministry of Youth Affairs and Sports for improving physical activity.
 ● Union Budget 2023-2024 Outcome based Budgeting: Government has for the first time introduced hypertension and diabetes treatment as output indicators reflecting government's commitment to scale-up hypertension and diabetes coverage services


Global Initiatives for NCDs

 ● Global Coordination Mechanism on Non-communicable Diseases: By WHO, which plays an important role in promoting action between governments, civil society organizations and other players working to improve health by preventing and controlling. 
●Non-communicable Disease (NCD) Data Portal: Aims to raise awareness on progress in tackling NCDs and their risk factors and strengthen accountability for action by countries.

Suggestions moving forward for NCDs

 ●Multi stakeholder approach: For Example, Civil society can help increase awareness and educate the public on healthy lifestyles. 
● Improving access to healthcare: Improving access to quality healthcare, including affordable medications and essential medical services, can help manage and treat NCDs effectively.
 ● Engaging communities: Engaging communities in the prevention and management of NCDs can be effective in raising awareness and promoting healthy behaviors. 
●Implementing policies and regulations: Policies and regulations that limit exposure to risk factors for NCDs, including tobacco and alcohol use, can be effective in preventing these diseases. For example- increasing taxes on tobacco and alcohol products etc. 
● Private sector participation: Collaboration of public and private sectors to address the growing burden of NCDs. The private sector can also play a remarkable role in promoting healthy products and services 
● Regional collaboration: Countries in the Southeast Asia region need to create a new and effective regional roadmap to accelerate NCD control. 

●Focus should be on prevention: Greater effort should be put into prevention which includes lifestyle changes through eating good food, exercising and other wellness practices

DATA BANK:

● Every years 17 million people under the age of 70 die of NCDs, and 86% of them live in low _ and middle _ income countries. 

●In  India, 66 percent of total deaths were due to NCDs in 2019.

● There was a 22% probability of death between  the age of 30 and 70 due to any type of NCDs. 


Non_ Communicable Diseases( NCDs):

☆ The Four main type:

 ● Cardiovascular diseases (CVDs)
 ● Cancer 
● Chronic respiratory disease 
● Diabetes 

☆ Other Types
Hypertension 
Dylispidemia 
Obesity 
Metabolic syndrome 
Rheumatoid arthritis ( RA)
Cerebrovascular disease 
Osteopenia/ osteoporosis 
Degenerative disc disease 
Sarcopenia and frailty 
Depression 
Cognitive impairment 
Neurodegenerative disease 

Benefits of preventing and Controlling( NCDs) 

Economic

● Reduced health care expenditure 

● Increased workforce participation 

● Boost in GDP

● More for health 


 Social

● People become healthier 

● Increased life expectancy 

● Increased earning capacity 

● Protect from financial risk of NCDs.

Global Measures to prevent NCDs:

● NCDs are  recognized as a major global challenge  in the United Nation's 2030 Agenda for sustainable development. 

● Global Group of Heards  of State and Governments on NCDs is an informal and voluntary initiative for exchange, collaboration and action on NCDs at the highest levels. 

● Led by Norway and Ghana,the group launched a Global Compact on NCDs  in April 2022, with the goal of saving 50 million people from dying prematurely of NCDs by 2030.

● WHO membrane states have also endorsed a menu of cost__ effective   NCD best buy policy options that can be used to tackle the pandemic.

WHO has launched a portal ( NCD data portal), which, for the first time, brings together all WHO data related to NCDs for 194 countries. 

Some successful interventions:

Zambia's effort to integrate national HIV services and cervical cancer prevention was helpful in screening more than 100,000 women for cervical cancer.

Many countries, including Malaysia, South Africa etc. have used taxation to reduce the consumption of sugar_ sweetened beverages and thereby tackling obesity and other NCDs.


Way Forward:

● International cooperation and advocacy : National and international leaders must use their positions of power to increase the visibility of NCDs and highlight what can be done to tackle them. 

Stronger health care delivery: It includes strengthening a country's health workforce, ensuring that health workers all have the knowledge and resources they need to address NCDs.

Health __ in _ all__ policies approach will play an important role in rendering visibility to the need for dialogue and consensus on the impact of policies on health in general and the NCD epidemic in particular. 

Protection for the vulnerable: Identifying groups most at risk from NCDs can enable targeted support. 

● Promoting high__ quality R&D: It can provide guidance and best Practices for the planning, implementation and evaluation of various health programmes. 

● Reduce the major modifiable risk factors,   such as tobacco use, harmful use of alcohol, unhealthy diets, and physical inactivity. 

TRANS-FAT


 • World Health Organization’s (WHO’s) trans- fat elimination validation programme open for country applications. 

• WHO Validation Programme for Trans Fat Elimination will recognize Member States for having a normative framework in place to eliminate industrially produced Trans Fatty Acid (TFA) from their national food supplies. o Countries can now apply to receive WHO validation certificate for trans-fat elimination.
 ■According to WHO, 44 countries including India have best-practice policies in effect for eliminating TFA and can receive official certificates. 
● Trans fats are unsaturated fats produced from vegetable oils and are commonly used in preparation of margarine and commercially baked or fried foods. o There are two forms of trans- fat i.e., 

☆Naturally-occurring trans- fats, occurs naturally in some dairy and meat products.
 ☆Industrially produced trans-fat add hydrogen to liquid vegetable oils to make them more solid. It is found in packaged foods, baked goods, cooking oils and spreads.  

• Trans fats are source of non-communicable disease and associated with increased risk of heart attacks and death from coronary heart disease. 

Steps taken to regulate TFA o WHO’s REPLACE Trans Fat-Free by 2023 strategy. (refer image) o FSSAI made mandatory for food manufacturers to declare TFA content on nutrition label. o FSSAI’s Eat Right India Movement discouraged trans-fat food. 


CANCER 

What is Cancer?

Cancer is an abnormal and uncontrolled division of cells, known as cancer cells, that invade and destroy  the surrounding tissues. Generally  Cancer is defined as uncontrolled proliferation of cells without any differentiation. Cancer cells are different  from normal cells in some aspects . They do not remain confined to one part of the body. They penetrate and infiltrate into the adjoining tissue and dislocate their functions. Some of the cancer cells get detached  from the main site of origin and travel by blood and lymph to sites distant from the original tumor and form fresh colonies, called metastasis or secondary  growth.

How Cancer Cells  Differ from Normal Cells? 

Normal cells have limited  life span .They are usually replaced by new cells through cell division  and cell differentiation.Their production is regulated in such a manner that the number of a given cell type remains nearly constant. Normal cells show a property called contract inhibition. Due to this property they contract with other cells, inhibitb their uncontrolled growth. Cancer cells seem to have lost this property. But cancer  cells  do not respond to normal growth control mechanism. These cells proliferate in an unregulated manner and form clones of cells which can expand irregularly. This uncontrolled growth is called tumour or neoplasm. 

Types of  Tumours :

There are two types of Tumours: benign and malignant. 

(i) Benign Tumour ( = Nonmalignant Tumour): It remains confined to the site of its origin and does not spread to other parts of the body.It causes limited damage  to be body. It is non_ cancerous. 

(ii) Malignant Tumour ( = Cancerous Tumour) : It first grows slowly. No symptoms are noticed. This stage is called the latent stage. The tumor later grows quickly. The cancer cells go beyond adjacent tissue and enter the blood and lymph. Once this happens, they migrate to many other sites in the body where the cancer cells continue to divide. A phenomenon  in which cancer cells spread to distant sites through body fluids to develop secondary  tumour is called metastasis. Only malignant tumours are properly designated as cancer. 

Properties of Cancer Cells:

(i) Uncontrolled proliferative ability. 

(ii) Extracellular growth factors are not required. 

(iii) Overgrowth and ability  to invade new sites ( metastasis).

(iv) Nucleus becomes irregular with abundant granules. 

(v) There is increase in number of lysosomes, reduction in mitochondrial cristae, more melanin and debris in cytoplasm. 

(vi) Cancer cells resist induction of cell death promotes development of tumours.


Types of Cancers :

Four types of cancers are classified on the basis of the tissue where they arose.

1): Carcinomas : Mainly derived  from epithelial cells; include cancers of cervical ( cervix is part of uterus), breast, skin brain, lung, stomach, etc.About 80% of all tumours are carcinomas. 


2): Melanomas : Cancerous growth of melanocytes  ( pigment cells of skin cells) is called melanomas. 


3): Sarcomas : Located in connective tissues. Thus, they include the cancers of bones, cartilage, tendons, adipose tissue and lymphoid tissue. Cancer of bones is called osteoma .Cancers of adipose tissue are known as lipomas.

4): Leukemias and Lymphomas : These are cancers  of haematopoietic cell.Leukemias ( = leukaemias) are characterised by abnormal increase of white blood corpuscles count due to their increased formation in the bone narrow. Leukemias are commonly  called blood cancers.Cancers of lymphatic tissue are termed as lymphomas. Hodgkin's disease is an example of human lymphoma.  In  Hodgkin's disease there is chronic enlargement of the production  of lymphocytes by lymph nodes and spleen.


● Adenoma __ Cancer of glands.

● Myoma__ Cancer of muscular  tissue. 

● Glioma__ Cancer of glial  cells of central nervous system. 

● The most common  cancers in India are mouth_ throat cancer in men and uterine _ cervical cancer in women.



Causes of Cancer :

Chemical  and physical  agents that can cause cancer are called carcinogens, which belong to three categories. 
 
(i) Oncogenic  Transformations : They are agents or factors which bring about changes in genetic formation, e.g., some growth factors, hormones. 

(ii) Tumour Promoters: They promote proliferation of cells which have undergone oncogenic transformation, e.g.,growth factors, hormones. 


(iii) Tumour Viruses : Some Viruses  are known to be connected with oncogenic transformations. 


Carcinogens are as follows: 

1. Physical  Irritants: 

(i) Use of Kangri ( an earthen pot containing  burning  coal) by Kasmiris causes abdominal  skin cancer as  these people keep Kangri close to their abdomen during winter. 


(ii) Betal and tobacco chewing causes oral cancer.

(iii) Heavy smoking  causes lung cancer  and may also cause cancer of oral cavity, pharynx ( throat) and larynx. 

(iv) Japped teeth may cause tongue  cancer. 

(v) Excessive  exposure  to sun light can cause skin cancer. 


2. Chemical  Agents:

Several chemicals are known to cause cancer .These are caffeine, nicotine, products of combustion of coal and oil and  pesticides; constant use of artificial sweetener can cause cancer. An animal protein__ rich diet is known to cause cancer of larger intestine. Breast cancer has hormonal relationship. Thus, some sex hormones and steroids secreted or given in large amounts  may cause  cancer.  Chemical  sweepers can develop cancer of scrotum. Dye workers have a high rate of bladder  cancer.

3. Radiations:

The X_ rays, cosmic rays, ultra__ violet rays, etc.can cause cancer. Japanese  people exposed to radiations from World War II nuclear bombing show five times the incidence of leukemia seen in the rest of the population. 

4. Biological Agents:

Some viruses and other parasites, excessive secretion of certain hormones are believed to cause cancers.

Cancer and Genes : 

Cancer _ associated  genes  are divided  into the following  three categories. 

(i) Cancer causing viruses  are called oncogenic viruses. The genes of oncogenic viruses  are known as viral oncogenes. It is now held that all cells carry some cancer causing  genes called oncogenes which when activated under certain  conditions could change  into oncogenic cells. Jumping genes are often involved  in this conversion. 


(ii) Tumour suppressor genes that inhibit  cell proliferation. 

(iii) Genes that regulate  programmed cell growth.

How Cancer Spreads :

Abnormal  increase in number of cells in a tissue  or organ forms a clone of proliferative cells. This excessive proliferation gives rise to a mass of cells which is initially known as benign tumour. The benign tumour cells enter into the blood vessels and migrate to other sites in the body where these cells continue to divide, such tumour cells are known as malignant  cells and tumours are called malignant tumours. The malignant tumours are designated as cancer.


Detection and Diagnosis  of Cancer:

It depends upon histological features of malignant structure. 

(i) Bone marrow biopsy and abnormal count of WBCs in leukemia. 

(ii) Biopsy of tissue, direct or through endoscopy. Also endoscopic observation. Pap test  (cytological staining) is used for detecting cancer  of cervix and other parts of genital  tract.

(iii) Techniques such as radiotherapy ( use of X_ rays), CT Scan ( computed tomography) MRI Scran ( magnetic  imaging) are very useful  to detect cancers of the internal organs.  In CT Scan X_ rays are used to generate  a three dimensional image of internal organs. In MRI strong  magnetic fields and non_ ionizing  radiations are used to detect pathological and physiological changes in the living tissue. Antibiotics against cancer specific  antigens are also used for detection of certain cancers. Techniques of molecular biology  can be applied  to detect genes in individuals.  Mammography is radiographic examination of breasts  for possible cancer. 



(iv) Monoclonal antibodies coupled to appropriate radioisotopes can detect cancer specific  antigens and hence cancer. 


Different Sites of  Cancer:

Some of the important  sites of cancer are skin, mouth, oesophagus, stomach, colon, rectum, liver, gall bladder ,pancreas, blood lymph, adipose tissue, lung, uterine cervix, breast, brain, penis, prostate, muscles, thyroid, kidney  and bones.


Possible Symptoms of Cancer :

(i) A persistent cough or hoarseness in a smoker. 

(ii) A peristent  change  in digestive and bowel habits. 

(iii) A change in a wart or mole, 

(iv)  A lump or hard area in the breast .

(v) Unexpected diminished or lost appetite. 

(vi) Unexplained  low_ grade fever. 

(vii)  Unexplained  loss  of weight. 

(viii) Any uncurable ulcer.

(ix) Bleeding in vagina at times other than the menstruation. 

(x) Non_ injury bleeding  from the surface  of the skin, mouth or any other opening of the body.


Treatment:

Four general methods of treatment for cancer are currently available. 

1): Surgery: It involves the removal  of the entire cancerous tissue.

2): Radiation therapy: It involves the exposure of the cancerous parts of the body of X_ rays which destroy rapidly  growing  cells without harming the surrounding tissue. 

3): Chemotherapy: It involves the administration of certain anticancer drugs. These drugs check cell division by inhabiting DNA synthesis. These drugs may be more toxic to cancerous cells than to normal cells. Thus chemotherapeutic drugs kill cancerous cells. Majority  of drugs have side effects like hair loss, anaemia etc. Most cancers are treated by combination of surgery, radiotherapy and chemotherapy. Patients are given substances called biological response modifiers like a interferon which activate their immunity system are help in destroying the tumours.

4): Immunotherapy: It involves  natural anti__ cancer immunological defence mechanisms. Monoclonal antibodies are used in various ways, e.g., radioimmunotherapy for treatment of cancer.
 
  These therapies can be used either  singly, or in a suitable  combination. 

Efforts are being made to develop  cancer vaccines. 


Theories of Carcinogenesis 

Some of these are being summarised as under :

(i) Mutation Theory  of Carcinogenes : Jacobson (1958 has suggested that mutations may cause genetic  disorders in a normal somatic cells. 

(ii) Selective gene__ activation theory : According  to this theory certain harmful  but unexpressed protooncogenes become active to oncogenes which cause the loss of the control over growth  and division leading  to the development  of cancerous tumour. Genetic basis of cancer  was explained by Michael Bishop and Harold Varmus (Noble Prize 1989).


(iii) Virus Theory of Carcinogensis : Murphey  and Rous discovered  the possibility of viruses being carcinogenic 













































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