Cancer Questions in English

(C) The correct answer is $C$. Vitamin $B_{17}$,also known as amygdalin or laetrile,has been studied for its potential anti-cancer properties. It is found in various plant sources,including the seeds of fruits like apricots and in certain vegetables. While its efficacy is a subject of ongoing scientific debate,it is historically and commonly associated with anti-cancer claims in nutritional literature.

(C) Retroviruses are a group of viruses that contain $RNA$ as their genetic material.
Upon infecting a host cell,they use the enzyme $RNA$-dependent $DNA$ polymerase (also known as reverse transcriptase) to synthesize $DNA$ from their $RNA$ template.
This newly synthesized $DNA$ is then integrated into the host cell's genome.
Therefore,statement $C$ is incorrect because $DNA$ is indeed produced and present during the life cycle of retroviruses.

(A) In normal cells,growth and differentiation are highly controlled and regulated.
Cancer cells lose this property of contact inhibition,which leads to uncontrolled cell division.
This results in a mass of undifferentiated cells,which is referred to as a tumour (neoplasm).

(A) Retroviruses are known to cause cancer because they possess viral oncogenes $(v-onc)$.
These viral oncogenes are derived from cellular proto-oncogenes $(c-onc)$ present in the host genome.
When these viruses infect a host cell,they can integrate their genetic material into the host genome,potentially activating these proto-oncogenes or introducing viral oncogenes,which leads to uncontrolled cell division and cancer.

(A, D) Oral cancer is primarily associated with the use of tobacco products.
Smoking and the chewing of betel quid (often containing tobacco) are major risk factors for the development of oral cancer.
These substances contain carcinogens that damage the $DNA$ of cells in the oral cavity,leading to uncontrolled cell growth.
Therefore,both smoking and eating betel (with tobacco) are causative factors.

(B) Cancerous cells are characterized by uncontrolled division and the ability to invade surrounding tissues.
When these cells break away from the primary tumor,they travel through the blood or lymphatic system to distant parts of the body.
This process of spreading cancer cells to distant sites is known as $Metastasis$.
$Metastasis$ is a hallmark of malignant tumors and is the primary cause of cancer-related mortality.

(D) Cancerous cells exhibit several cytological changes compared to normal cells.
One of the most characteristic features of malignant cells is the alteration in the nucleus.
The nucleus of a cancerous cell typically becomes enlarged,irregular in shape,and shows increased chromatin content.
This condition is often referred to as being abnormally large or hyperchromatic,which is a key diagnostic marker in histopathology.

(A) Cancer cells exhibit the property of uncontrolled and rapid cell division (uncontrolled proliferation).
Radiation therapy works by damaging the $DNA$ of cells.
Since cancer cells are dividing much more rapidly than normal cells,they are more susceptible to $DNA$ damage caused by ionizing radiation,which prevents them from dividing further and leads to cell death.

(A) Cancer is characterized by the uncontrolled,abnormal,and excessive division of cells.
In normal cells,growth and differentiation are highly controlled and regulated.
However,in cancer cells,these regulatory mechanisms break down,leading to the formation of a mass of cells known as a tumor.
Therefore,cancer is fundamentally related to the uncontrolled growth of tissues.

(A) The most common type of cancer reported in men in India is lung cancer. This is primarily attributed to the high prevalence of tobacco consumption,including smoking and the use of smokeless tobacco products,which are major risk factors for the development of lung and oral cancers.

(C) Cancer is classified based on the tissue of origin.
$1$. Carcinoma: Cancer arising from epithelial tissues (e.g.,skin,lining of organs).
$2$. Sarcoma: Cancer arising from connective tissues,such as bone,cartilage,fat,muscle,or fibrous tissues (like fibroblasts).
$3$. Leukemia/Lymphoma: Cancer arising from blood-forming cells or the immune system.
Therefore,a tumour originating in connective tissues like fibroblasts is termed a 'sarcoma'.

(D) Metastasis is the process by which cancer cells spread from the primary site of origin to other distant parts of the body through the blood or lymphatic system.
This spread of cancer to distant organs or tissues is the defining characteristic of Stage $IV$ cancer,which is also known as metastatic or advanced cancer.
In earlier stages,the cancer is typically localized or has only spread to nearby lymph nodes,but it has not yet reached distant organs.

(D) Chemicals that induce cancer are known as carcinogens.
These agents can be physical,chemical,or biological in nature.
Carcinogens cause mutations in the $DNA$ of cells,leading to uncontrolled cell division.
This uncontrolled growth results in the formation of a malignant tumor,which is a characteristic feature of cancer.

(D) Cancer cells are characterized by the loss of contact inhibition,which leads to uncontrolled and rapid cell division. This abnormal,unregulated mitosis results in the formation of a mass of cells known as a tumor or cancer.

(C) The property of cancer cells to spread from one part of the body to other distant sites via blood or lymph is known as $Metastasis$.
This is the most feared property of malignant tumors,as it makes the cancer difficult to treat and often leads to the death of the patient.
$Mutation$ refers to changes in the $DNA$ sequence.
$Malignancy$ refers to the cancerous nature of a tumor.
$Benign$ $tumours$ are non-cancerous growths that do not spread to other parts of the body.

(B) Leukemia is a type of cancer that affects the blood and bone marrow.
It is characterized by the abnormal and uncontrolled proliferation of white blood cells (leukocytes) in the body.
This condition leads to a decrease in the production of normal blood cells,which can cause anemia,bleeding,and increased susceptibility to infections.

(B) Oncogenes are mutated forms of proto-oncogenes that are present in normal cells. When these genes are activated or mutated due to various factors like radiation,chemicals,or viruses,they lead to uncontrolled cell division and growth,resulting in the formation of tumors or cancer.

(A) The property of cancerous cells to spread from one part of the body to other distant sites through blood or lymph is known as $Metastasis$.
This is the most feared property of malignant tumors,as it makes the cancer difficult to treat once it has spread to other organs.

(C) Lymphoma is a type of cancer that originates in the lymphatic system,which includes the lymph nodes,spleen,thymus gland,and bone marrow.
It occurs when lymphocytes (a type of white blood cell) grow abnormally and uncontrollably.
Therefore,cancer found in lymph nodes and the spleen is classified as Lymphoma.

(A) The question refers to the historical context of medical advancements where $Cancer$ was often cited in academic literature as a disease that would see significant breakthroughs in treatment and potential curability within a few decades due to advancements in biotechnology and gene therapy. While $Poliomyelitis$ is largely controlled through vaccination and $Tuberculosis$ is already curable with antibiotics,$Cancer$ remains the primary focus of ongoing research for a definitive cure.

(B) Oncogenes are genes that have the potential to cause cancer.
$F.P.$ Rous discovered the first oncogene in $1911$ while studying the Rous Sarcoma Virus $(RSV)$ in chickens.
Later,$J.M.$ Bishop and $H.E.$ Varmus were awarded the Nobel Prize in $1989$ for their discovery of the cellular origin of retroviral oncogenes,which demonstrated that these genes are present in normal cells as proto-oncogenes.
However,the initial discovery of the oncogene itself is attributed to $F.P.$ Rous.

(D) Cancer cells are characterized by the loss of contact inhibition,which leads to uncontrolled cell division (growth).
These cells can invade surrounding healthy tissues.
Furthermore,they can travel through the blood or lymph system to distant parts of the body,a process known as metastasis.
Therefore,all the mentioned characteristics are true for cancer cells.

(D) Cancer is caused by the transformation of normal cells into cancerous cells.
This transformation is triggered by certain genes known as cellular oncogenes $(c-onc)$ or proto-oncogenes.
When these genes are activated under certain conditions,they lead to oncogenic transformation of the cells,resulting in cancer.
Therefore,the genes concerned with the production of cancer are called Oncogenes.

(B) benign tumour is a non-cancerous growth that remains confined to its original location.
It does not spread to other parts of the body,meaning it does not show metastasis.
Benign tumours are typically well-differentiated,meaning the cells resemble normal cells,and they are surrounded by a fibrous capsule (encapsulated),which prevents them from invading surrounding tissues.

(A) Tobacco contains carcinogenic substances like benzpyrene.
Approximately $95\%$ of lung cancer cases are attributed to smoking.
Reverse smoking is known to cause oral cancer.
Bidi smoking is linked to cancers of the tongue,pharynx,larynx,tonsils,and esophagus.
Tobacco chewing is a primary cause of oral cancer.

(D) Carcinogens are agents that cause cancer.
$X-$ray radiation and $U.V.$ radiation are physical carcinogens that cause $DNA$ damage.
Nicotine is a chemical substance found in tobacco that acts as a carcinogen.
Therefore,all the listed options are carcinogenic agents.

(C) Polycyclic aromatic hydrocarbons are known to be potent carcinogens. When inhaled through tobacco smoke,these compounds interact with cellular $DNA$,leading to mutations that can result in the uncontrolled cell division characteristic of cancer.

(B) Myelomas are cancerous plasma cells derived from the bone marrow. In biotechnology,specifically in the production of monoclonal antibodies,myeloma cells are fused with antibody-producing $B$-lymphocytes to create hybridomas. Hybridomas are immortalized cells that can produce specific antibodies continuously.

(D) The genes associated with the development of cancer are known as $Oncogenes$.
In normal cells,these genes exist as $Proto-oncogenes$ or $Cellular$ $oncogenes$ $(c-onc)$.
When these genes are activated under certain conditions (such as physical,chemical,or biological agents),they lead to oncogenic transformation of the cells,resulting in cancer.
Therefore,the correct option is $D$.

(C) Cancer diagnosis involves techniques like Radiography ($X$-rays),$CT$ (Computed Tomography) scanning,$MRI$ (Magnetic Resonance Imaging),and Biopsy (histopathological studies).
$UV$ ray treatment is a therapeutic method used for certain skin conditions or sterilization,but it is not a diagnostic tool for cancer.
Therefore,$UV$ ray treatment is the correct answer.

(B) Cancer is broadly classified based on the tissue of origin.
$1$. Carcinoma is cancer of epithelial tissue.
$2$. Sarcoma is cancer of connective tissue (e.g.,bone,cartilage,fat,muscle,and fibrous tissue).
$3$. Leukemia is cancer of blood-forming tissues.
Therefore,Sarcoma originates from connective tissue.

(C) Radiation therapy,specifically using electron beams,is a standard medical treatment used to destroy cancer cells.
Electron beams are a type of external beam radiation therapy that delivers high-energy electrons to the tumor site.
These electrons have a limited depth of penetration,making them ideal for treating superficial tumors such as those found in the skin or near the surface of the body.
Therefore,the correct option is $C$.

(A) Cancerous cells exhibit the property of uncontrolled and rapid cell division. Radiation therapy works by damaging the $DNA$ of cells. Since cancerous cells are actively and rapidly dividing,they are much more susceptible to $DNA$ damage caused by ionizing radiation compared to normal,healthy cells that divide at a slower or controlled rate. This damage prevents the cancer cells from dividing further,eventually leading to their death.

(D) Ionizing radiations like $X-rays$ and $\gamma-rays$ are well-known carcinogens.
These radiations cause $DNA$ damage,which leads to neoplastic transformation of cells.
Exposure to high doses of radiation is specifically linked to the development of blood cancers,such as leukemia,due to the mutation of hematopoietic stem cells in the bone marrow.

(D) Cancer is caused by the transformation of normal cells into cancerous neoplastic cells. This transformation is triggered by physical, chemical, or biological agents known as $Carcinogens$.
$1$. Physical agents include ionizing radiations like $X-rays$ and $\gamma$ rays, and non-ionizing radiations like $UV$ rays.
$2$. Chemical agents include substances like tobacco smoke.
$3$. Biological agents include oncogenic viruses.
Therefore, the correct term for factors responsible for causing cancer is $Carcinogens$.

(B) In normal cells,there are genes called proto-oncogenes that regulate cell growth and division. When these genes undergo mutation or are activated by certain factors (like carcinogens,radiation,or viruses),they transform into oncogenes. These oncogenes lead to uncontrolled cell division,which is the hallmark of cancer. Therefore,the genes involved in the development of cancer are called oncogenes.

(D) The diagnosis of cancer involves several methods:
$(1)$ Biopsy: $A$ piece of the suspected tissue is cut into thin sections,stained,and examined under a microscope by a pathologist (histopathological study).
$(2)$ Histopathological study: This is the gold standard for confirming cancer.
$(3)$ Blood and bone marrow tests: These are commonly used for cancers of the blood,such as leukemia,to identify increased cell counts.
Therefore,all four methods listed are used in the diagnosis of various types of cancer.
Thus,the correct option is $D$.

(D) Cancer treatment involves a multidisciplinary approach to effectively eliminate or control the growth of malignant cells.
For most cancers,a combination of treatments is used to ensure maximum efficacy.
These include:
$1$. Surgery $(A)$: To physically remove the tumor mass.
$2$. Radiotherapy $(B)$: To kill cancer cells using high-energy radiation.
$3$. Chemotherapy $(C)$: To destroy cancer cells using specific chemical agents.
Therefore,the most effective approach often involves the combination of surgery,radiotherapy,and chemotherapy ($A, B$ and $C$).

(D) In normal cells,there are genes known as proto-oncogenes $(c-onc)$ or cellular oncogenes.
These genes are present in an inactive state in normal cells.
Under certain conditions,such as physical,chemical,or biological agents,these proto-oncogenes can be activated to become oncogenes,which lead to oncogenic transformation of the cells,causing cancer.
Therefore,$c-onc$ refers to both cellular oncogenes and proto-oncogenes.

(D) Cancer treatment involves a combination of various approaches to eliminate or control the growth of malignant cells.
$1$. Surgery: Used to remove the tumor mass physically.
$2$. Radiotherapy: Uses high-energy radiation to kill cancer cells or shrink tumors.
$3$. Chemotherapy: Uses specific drugs to kill actively dividing cancer cells.
$4$. Immunotherapy: Biological response modifiers are used to activate the immune system to destroy cancer cells.
Therefore,all the listed methods are standard treatments for cancer.

(D) Cancer diagnosis involves several techniques. Biopsy and histopathological studies are considered the most accurate and definitive methods for cancer diagnosis. Techniques like $MRI$ (Magnetic Resonance Imaging),$CT$ (Computed Tomography),and $X$-rays are used to detect cancers of internal organs,but they are imaging techniques. Microscopic examination of body fluids (like in leukemia) is also used,but biopsy remains the gold standard. Since none of the provided options ($MRI$,$X$-ray,or simple microscopic examination) represent the definitive 'gold standard' biopsy/histopathology,the correct choice is $D$.

(B) Tumors are classified into two types: $Benign$ and $Malignant$.
$Benign$ tumors normally remain confined to their original location and do not spread to other parts of the body,causing little damage.
$Malignant$ tumors are cancerous. They are a mass of proliferating cells called neoplastic or tumor cells. These cells grow very rapidly,invading and damaging the surrounding normal tissues.
As these cells actively divide and grow,they also starve normal cells by competing for vital nutrients. Cells sloughed from such tumors reach distant sites through the blood,and wherever they get lodged in the body,they start a new tumor there. This property called $Metastasis$ is the most feared property of malignant tumors.
$Lipoma$ is a benign tumor made of fat tissue.
Therefore,only $Malignant$ tumors are considered cancerous.

(B) Carcinoma is a type of cancer that originates in the epithelial cells,which line the surfaces of the body,including the skin and the mucous membranes of internal organs.
Sarcoma,on the other hand,refers to malignant tumors arising from connective tissues (such as bone,cartilage,or fat).
Therefore,the correct statement regarding carcinoma is that it is a malignant tumor of the skin and mucous membrane.

(A) Leukemia is a type of cancer that affects the blood and bone marrow.
It is characterized by the uncontrolled proliferation of abnormal white blood cells (leukocytes).
Thrombosis refers to the formation of a blood clot within a blood vessel.
Hemophilia is a genetic disorder that impairs the body's ability to make blood clots.
Hemolysis is the destruction of red blood cells.
Therefore,the correct answer is $A$.

(D) Neoplastic transformation (cancer) can be induced by physical,chemical,or biological agents.
Physical agents include ionizing radiations like $X$-rays and gamma rays,and non-ionizing radiations like $UV$ (ultraviolet) rays.
Both ionizing and non-ionizing radiations cause damage to $DNA$,leading to neoplastic transformation.
Therefore,$1$ (ionizing radiation),$2$ ($X$-rays,which are ionizing),$3$ (non-ionizing radiation),and $4$ ($UV$ rays,which are non-ionizing) are all responsible for $DNA$ damage.

(B) Tobacco smoking is a major risk factor for the development of lung cancer. The carcinogens present in tobacco smoke,such as polycyclic aromatic hydrocarbons and nitrosamines,damage the $DNA$ of lung cells,leading to uncontrolled cell division and tumor formation.

(B) Interferons are antiviral proteins secreted by virus-infected cells that protect non-infected cells from further viral infection.
In the context of cancer treatment,biological response modifiers such as alpha-interferons are used to activate the immune system and help in destroying cancer cells.
Therefore,interferons are useful in controlling cancer.

(B) Ionizing radiation, such as $X-rays$ and $\gamma$ rays, is known to be a potent mutagen. Exposure to high levels of radiation can damage $DNA$ in cells, leading to mutations. One of the most significant health risks associated with chronic or high-level radiation exposure is the development of cancer, specifically $Leukemia$ (a type of blood cancer). Therefore, radiation is considered a major health hazard.

(D) Vitamins $A$,$C$,and $E$ are known as antioxidant vitamins.
Antioxidants help in neutralizing free radicals,which are unstable molecules that can cause cellular damage and contribute to the development of cancer.
Vitamin $A$ (retinoids) helps in cell differentiation and immune function.
Vitamin $C$ (ascorbic acid) and Vitamin $E$ (tocopherol) protect cells from oxidative stress,thereby reducing the risk of cancer progression.
Therefore,all these vitamins are considered beneficial in the context of cancer prevention and supportive care.

(C) Cancer is characterized by the uncontrolled,abnormal division of cells,which leads to the formation of a mass of cells called a tumor. Unlike normal cells,cancer cells do not exhibit contact inhibition,meaning they continue to divide even when they come into contact with other cells. This uncontrolled growth can invade and damage surrounding tissues and,in advanced stages,spread to other parts of the body through a process called metastasis. Therefore,cancer is a non-infectious,fatal disease.