Cancer Questions in English

(B) Chronic Myelogenous Leukemia $(CML)$ is a type of cancer that affects the blood-forming cells in the bone marrow.
It is characteristically associated with a specific chromosomal abnormality known as the Philadelphia chromosome.
This abnormality is formed by a reciprocal translocation between the long arms of chromosome $9$ and chromosome $22$,denoted as $t(9;22)(q34;q11)$.
This translocation results in the fusion of the $BCR$ gene on chromosome $22$ with the $ABL1$ gene on chromosome $9$,creating the $BCR-ABL1$ fusion gene,which produces a constitutively active tyrosine kinase that drives uncontrolled cell proliferation.

(A) Reciprocal translocation between chromosome $8$ and chromosome $14$ is a hallmark genetic abnormality associated with Burkitt's lymphoma.
In this translocation,the $MYC$ proto-oncogene located on chromosome $8$ is moved to the immunoglobulin heavy chain locus on chromosome $14$.
This results in the overexpression of the $MYC$ protein,which drives uncontrolled cell proliferation,leading to the development of this specific type of $B$-cell non-Hodgkin lymphoma.

(C) The correct answer is $C$.
$AFP$ $(Alpha-fetoprotein)$ is a tumor marker typically associated with liver cancer (hepatocellular carcinoma) or germ cell tumors,not prostate cancer.
Prostate cancer is typically associated with elevated levels of $PSA$ $(Prostate-Specific Antigen)$.
Chewing tobacco is a known cause of oral cancer.
An abnormal increase in immature white blood cells is characteristic of leukemia.
Smoking is the primary cause of lung cancer.

(B) $Glioma$ is a type of tumor that occurs in the brain and spinal cord. It begins in the glial cells that surround nerve cells and help them function. Therefore,it is classified as a type of brain cancer.

(D) Leukemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells $(WBCs)$.
It is often caused by chromosomal translocations,such as the formation of the Philadelphia chromosome $(t(9;22))$.
It originates from the cancerous transformation of hematopoietic stem cells in the bone marrow.
Therefore,all the given options are correct factors associated with the development of leukemia.

(B) tumor marker is a substance found at higher than normal levels in the blood,urine,or body tissues of some people with cancer.
$PSA$ (Prostate-Specific Antigen) is a protein produced by the prostate gland. Elevated levels of $PSA$ in the blood are commonly used as a tumor marker to screen for and monitor prostate cancer.
$AFP$ (Alpha-fetoprotein) is also a tumor marker,but $PSA$ is the most classic example frequently cited in clinical diagnostics for specific organ-based screening.
Therefore,$PSA$ is the most appropriate answer among the given options.

(B) Retroviruses are a group of viruses that can infect animal cells,including human cells.
They possess the ability to integrate their viral genome into the host cell's $DNA$.
When these viruses infect normal cells,they can introduce oncogenes or activate existing proto-oncogenes,thereby transforming normal cells into cancerous cells.
Therefore,retroviruses are commonly used in biotechnology as vectors to transform normal human cells into cancerous cells for research purposes.

(B) The correct answer is $PCR$ (Polymerase Chain Reaction).
$PCR$ is a highly sensitive molecular diagnostic technique.
It is used to detect $HIV$ in suspected $AIDS$ patients even when the concentration of the virus is very low.
It is also used to detect specific mutations in genes of suspected cancer patients,which helps in early diagnosis and treatment planning.

(D) Cancerous cells that break away from the original site and spread to other parts of the body through the bloodstream and lymphatic system constitute malignant tumours.
The spread of cancer to other sites or organs in the body is called metastasis.
Other statements are incorrect because:
$1$. Cancer cells lose the property of contact inhibition,which is why they continue to divide uncontrollably.
$2$. Not all tumours are cancerous; for example,benign tumours remain confined to their original location.
$3$. Not all viruses are oncogenic (cancer-causing).

(D) Techniques such as radiography (use of $X-rays$),$CT$ (Computed Tomography),and $MRI$ (Magnetic Resonance Imaging) are widely used for the detection of cancers.
$CT$ uses $X-rays$ to generate a three-dimensional image of the internals of an object.
$MRI$ uses strong magnetic fields and non-ionizing radiations to accurately detect pathological and physiological changes in the living tissue.

(A) An oncogene is a gene that has the potential to cause cancer. In tumor cells,these genes are often mutated or expressed at high levels. Viruses that have the ability to transform normal cells into cancerous cells are known as oncogenic viruses.

(B) Cancer cells exhibit uncontrolled and rapid cell division. Radiation therapy works by damaging the $DNA$ of cells,which prevents them from dividing further. Because cancer cells divide much more rapidly than normal cells,they are significantly more susceptible to radiation-induced damage.

(A) The transformation of normal cells into cancerous neoplastic cells can be induced by physical,chemical,or biological agents. These agents are known as carcinogens.
Ionizing radiations,such as $X$-rays and $\gamma$-rays,and non-ionizing radiations,such as $UV$-rays,cause damage to $DNA$,which leads to neoplastic transformation.

(D) Cancer is caused by the uncontrolled division of cells,which results from mutations in specific genes that regulate the cell cycle.
$1$. Proto-oncogenes: These are normal genes that promote cell growth and division. When mutated or overexpressed,they become oncogenes,leading to uncontrolled cell proliferation.
$2$. Tumour suppressor genes: These genes normally act as 'brakes' on the cell cycle,preventing excessive division. Mutations that inactivate these genes allow cells to divide uncontrollably.
$3$. $p53$ gene: This is a well-known tumour suppressor gene often referred to as the 'guardian of the genome'. It plays a critical role in $DNA$ repair and apoptosis. Mutations in $p53$ are found in a large percentage of human cancers.
Since alterations in all these types of genes contribute to the development of cancer,the correct answer is 'All of the above'.

(D) Statement $I$ is correct: Malignant tumors exhibit the property of metastasis,which is the spread of cancerous cells to distant parts of the body through blood or lymph.
Statement $II$ is correct: Agents that induce cancer are known as carcinogens. These include physical agents (e.g.,$X$-rays,$UV$-rays),chemical agents (e.g.,tobacco smoke,aniline dyes),and biological agents (e.g.,oncogenic viruses).
Statement $III$ is correct: Benign tumors are non-cancerous and remain confined to their original location. They do not spread to other parts of the body and generally cause minimal damage compared to malignant tumors.
Therefore,all three statements are correct.

(D) The cancer of epithelial cells is called carcinoma.
It is a tumor that arises in the tissues that line the body's organs like the nose,colon,penis,breast,etc.
About $80 \%$ of all cancers are carcinomas.
Leukaemia refers to cancers of the blood or blood-forming organs.
Sarcoma originates in mesodermal tissues like bone,connective tissue,muscle,cartilage,fibrous tissue,or fat.

(A) Hodgkin's disease is a type of lymphoma,which is a cancer that starts in the cells of the lymphatic system,specifically the lymphoid tissue. It is characterized by the presence of Reed-Sternberg cells.

(C) Angiosarcoma is a type of sarcoma,which is a malignant tumour arising from tissues of mesodermal origin.
Statement $I$ is true because all malignant tumours exhibit uncontrolled and erratic cell division.
Statement $III$ is true because sarcomas are specifically defined as cancers of connective tissues or organs derived from the mesoderm.
Statement $II$ refers to carcinomas (cancers of epithelial origin),not sarcomas.
Statement $IV$ refers to lymphomas,which are cancers of the lymphatic system.
Therefore,statements $I$ and $III$ are correct for angiosarcoma.

(D) Malignant tumors initially grow slowly,and no symptoms are noticed; this is known as the latent stage.
Later,the tumor grows rapidly.
The cancer cells invade adjacent tissues and enter the blood and lymph circulation.
Once they enter the circulatory system,they migrate to various other sites in the body,where they continue to divide and form secondary tumors.
This property of spreading to distant sites is called metastasis.
Only malignant tumors exhibit metastasis and are classified as cancer.

(D) Malignant tumors are masses of proliferating cells known as neoplastic or tumor cells.
These cells grow very rapidly,invading and damaging the surrounding normal tissues.
As these cells actively divide and grow,they compete for vital nutrients,thereby starving the normal cells.
Cells sloughed from such tumors can reach distant sites through the blood or lymph,and wherever they lodge,they start a new tumor. This property is known as metastasis,which is the most feared characteristic of malignant tumors.
Therefore,all three statements $(I, II, III)$ are correct.

(D) Statement $I$ is true: Monoclonal antibodies against cancer-specific antigens are used for the detection of certain types of cancer.
Statement $II$ is true: Surgical removal of tumor cells is a common treatment method to reduce the tumor load and prevent further spread.
Statement $III$ is true: Chemotherapeutic drugs are used to kill cancerous cells,but they often cause side effects such as hair loss and anaemia because they also affect healthy cells.
Therefore,all three statements are correct.

(B) $AIDS$ is a communicable/infectious disease and is fatal.
Cystic fibrosis is a genetic disorder.
Cholera is a communicable disease caused by bacteria.
Cancer is a non-infectious disease and is one of the most common causes of death globally in human beings.

(A) $Metastasis$: It is the property of cancerous cells to spread to distant sites through blood and start a new tumor formation wherever they get lodged in the body.
$Metachrosis$: The ability of animals to change the intensity of their color.
$Metamorphosis$: The process of transformation from an immature form to an adult form in two or more distinct stages.
$Metagenesis$: $A$ phenomenon in which the polyp form of a $Cnidarian$ alternates asexually with the medusoid form.

(C) Cancer is characterized by the uncontrolled and abnormal division of cells due to the breakdown of regulatory mechanisms in the cell cycle.
Normal cells exhibit a property called contact inhibition,which prevents them from growing uncontrollably when they come into contact with other cells.
Cancer cells lose this property of contact inhibition,leading to continuous,rapid,and uncontrolled cell division (mitosis).
Meiosis is a reductional division that occurs only in germ cells,not in somatic cells where cancer typically originates.
Therefore,cancer is caused by uncontrolled mitosis.

(D) Cellular oncogenes $(c-onc)$ or proto-oncogenes have been identified in normal cells,which,when activated under certain conditions,could lead to oncogenic transformation of the cells.
Cancer-causing viruses,called oncogenic viruses,contain genes known as viral oncogenes.
$1$. Inducer gene: $A$ molecule that regulates gene expression.
$2$. Jumping genes: Genes that can change their position within the genome (transposons).
$3$. Structural gene: Genes that code for any $RNA$ or protein product other than a regulatory protein.
Therefore,oncogenes are specifically associated with the transformation of normal cells into cancerous cells.

(C) Assertion $(A)$ is incorrect because cancer is a non-communicable disease; it is not contagious and cannot spread from one person to another through contact,air,or water.
Reason $(R)$ is correct because cancerous cells lose their specialized functions and structural characteristics,a process known as dedifferentiation,which allows them to divide uncontrollably.

(D) Cigarette smoke contains numerous carcinogens that directly damage the tissues of the respiratory system.
Chronic exposure to cigarette smoke is the primary cause of lung cancer.
Other associations include: Soot and coal tar are linked to skin cancer,while leukemia (blood cancer) is caused by the uncontrolled proliferation of white blood cells $(WBCs)$.

(A) Cancer is fundamentally the uncontrolled growth of normal cells that have lost the ability to regulate cell division. As a result,abnormal cells develop and spread throughout the body.
In a healthy body,cell growth and differentiation are highly controlled and regulated mechanisms.
In cancer cells,there is a breakdown of these regulatory mechanisms.
Normal cells exhibit a property called contact inhibition,by virtue of which contact with other cells inhibits their uncontrolled growth.
Cancerous cells appear to have lost this property of contact inhibition. Consequently,they continue to divide indefinitely,giving rise to masses of cells known as tumors.

(N/A) Tumors are of two types: $(i)$ Benign tumor,$(ii)$ Malignant tumor.
Benign tumors do not contain cancerous cells.
Benign tumors normally remain confined to their original location,do not spread to other parts of the body,and cause little damage.
In contrast,malignant tumors contain cancerous cells,which are rapidly proliferating cells known as neoplastic or tumor cells.
$-$ These cells grow very rapidly,invading and damaging the surrounding normal tissues.
As these cells actively divide and grow,they compete with normal cells for vital nutrients,effectively starving them.
Cells sloughed off from this tumor reach distant sites through the blood,and wherever they lodge in the body,they initiate new tumor growth.
This property of spreading cancerous cells to distant sites is known as metastasis.

(N/A) The transformation of normal cells into cancerous neoplastic cells can be induced by physical, chemical, and biological agents.
Cancer-causing agents are known as $Carcinogens$.
$1$. Physical agents: Ionizing radiations like $X$-rays and $\gamma$ rays, and non-ionizing radiations like $UV$ rays cause $DNA$ damage, leading to neoplastic transformation.
$2$. Chemical agents: Chemical carcinogens present in tobacco smoke are identified as a major cause of lung cancer.
$3$. Biological agents: Cancer-causing viruses, known as oncogenic viruses, possess genes called viral oncogenes. Additionally, normal cells contain genes called cellular oncogenes $(c-onc)$ or proto-oncogenes, which, when activated under certain conditions, lead to the oncogenic transformation of cells.

(N/A) Early detection of cancers is essential as it allows the disease to be treated successfully in many cases.
Cancer detection is based on biopsy and histopathological studies of the tissue,and blood and bone marrow tests for increased cell counts in the case of leukemias.
In biopsy,a piece of suspected tissue is cut into thin sections,stained,and examined under a microscope by a pathologist.
Techniques like radiography (use of $X$-rays),Computed Tomography $(CT)$,and Magnetic Resonance Imaging $(MRI)$ are very useful to detect cancers of internal organs.
Computed tomography uses $X$-rays to generate a three-dimensional image of the internals of an object.
$MRI$ uses strong magnetic fields and non-ionizing radiations to accurately detect pathological and physiological changes in living tissues.

(N/A) $1$. Antibodies against cancer-specific antigens are used for the detection of certain cancers.
$2$. Techniques of molecular biology,such as gene sequencing and $PCR$,can be applied to detect genes in individuals with inherited susceptibility to certain cancers.
$3$. Identification of such genes,which predispose an individual to certain cancers,is very helpful in the prevention and early management of the disease.
$4$. Individuals identified with such genetic predispositions may be advised to avoid exposure to particular carcinogens to which they are susceptible,thereby reducing the risk of cancer development.

(N/A) The common approaches for the treatment of cancer include surgery,radiation therapy,chemotherapy,and immunotherapy.
$1$. Surgery: In this method,the tumor mass is surgically removed from the body.
$2$. Radiotherapy: In radiotherapy,tumor cells are irradiated lethally,while taking proper care to protect the normal tissues surrounding the tumor mass.
$3$. Chemotherapy: Several chemotherapeutic drugs are used to kill cancerous cells. Some of these are specific for particular tumors. However,the majority of these drugs have side effects like hair loss,anemia,etc.
$4$. Combination Therapy: Most cancers are treated by a combination of surgery,radiotherapy,and chemotherapy.
$5$. Immunotherapy: Tumor cells have been shown to avoid detection and destruction by the immune system. Therefore,patients are given substances called biological response modifiers,such as $\alpha$-interferons,which activate their immune system and help in destroying the tumor.

(A) Cancer-causing agents are called carcinogens. These can be physical,chemical,or biological.
Physical carcinogens include ionizing and non-ionizing radiations.
Ionizing radiations like $X$-rays and $\gamma$-rays cause $DNA$ damage,leading to neoplastic transformation.
Non-ionizing radiations like $UV$ rays cause $DNA$ damage by forming pyrimidine dimers,which can also lead to cancer.
Therefore,$P$ represents ionizing radiations ($X$-rays and $\gamma$-rays) and $Q$ represents non-ionizing radiations ($UV$ rays).

(D) Normal cells show a property called $Contact \ Inhibition$,which prevents them from growing uncontrollably when they come into contact with other cells.
Cancerous cells have lost this property of $Contact \ Inhibition$.
As a result,they continue to divide and grow,leading to the formation of masses of cells called tumors.
$Metastasis$ is the property of cancer cells to spread to distant sites in the body,which is a characteristic of malignant tumors.
Therefore,$Contact \ Inhibition$ is the property that cancerous cells do not exhibit.

(D) Oncogenes are mutated forms of proto-oncogenes that have the potential to cause cancer.
These genes are present in the normal cells of the body and,when activated or mutated,lead to uncontrolled cell division,resulting in the formation of tumors.
Therefore,oncogenes are specifically defined as cancer-causing genes.

(C) Biological response modifiers are substances that stimulate the body's immune system to fight cancer.
$\alpha$-Interferons are a type of cytokine produced by the body in response to viral infections and are used as biological response modifiers in cancer treatment.
They help in activating the immune system,which in turn helps in destroying the tumor cells.
Therefore,the correct option is $C$.

(A) Leukemia is a type of cancer that affects the blood and bone marrow. It is characterized by an abnormal increase in the number of white blood cells $(WBCs)$ in the body.
$A$. Leukemia: Blood cancer.
$B$. Melanoma: Cancer of the pigment-producing cells (melanocytes) in the skin.
$C$. Carcinoma: Cancer that begins in the skin or in tissues that line or cover internal organs.
$D$. Lymphoma: Cancer of the lymphatic system.

(D) The transformation of normal cells into cancerous neoplastic cells may be induced by physical,chemical,or biological agents.
$1$. Physical agents: These include ionizing radiations like $X$-rays and gamma rays,and non-ionizing radiations like $UV$ rays,which cause $DNA$ damage.
$2$. Chemical agents: These include various carcinogens found in tobacco smoke,such as polycyclic aromatic hydrocarbons,which are major causes of lung cancer.
$3$. Biological agents: These include oncogenic viruses (viral oncogenes) that carry genes capable of causing cancer in host cells.
Therefore,all these agents are responsible for carcinogenesis.

(D) Statement $A$ is correct: Techniques like Computed Tomography $(CT)$ and Magnetic Resonance Imaging $(MRI)$ are used to detect cancers of internal organs.
Statement $B$ is incorrect: Chemotherapeutic drugs are used to kill cancerous cells,although they often have side effects on non-cancerous cells.
Statement $C$ is correct: $\alpha$-interferons are biological response modifiers that activate the immune system of the patient and help in destroying the tumour.
Statement $D$ is incorrect: $\alpha$-interferons are biological response modifiers,not chemotherapeutic drugs.
Statement $E$ is incorrect: In leukaemia (blood cancer),there is a marked increase in the count of white blood cells,not a decrease.
Therefore,only statements $A$ and $C$ are correct.

(B) Neoplastic or cancerous cells exhibit several key characteristics that distinguish them from normal cells.
$1.$ They undergo uncontrolled and rapid proliferation,forming a mass of cells known as a tumor ($A$ and $B$).
$2.$ Malignant (neoplastic) cells possess the property of metastasis,where they invade and damage the surrounding normal tissues $(C)$.
$3.$ Cells that are confined to their original location are typically benign and do not exhibit the invasive characteristics of malignant neoplasms $(D)$.
Therefore,the characteristics of neoplastic (malignant) cells include rapid proliferation,mass formation,and invasion of surrounding tissues $(A, B, C)$.

(A) Metastasis is the process by which cancer cells break away from the primary tumor, travel through the blood or lymphatic system, and form new tumors in other parts of the body.
This property makes malignant tumors highly dangerous and difficult to treat, as they can spread to vital organs.
Therefore, the assertion that metastasis is the most feared property of malignant tumors is true.
The reason correctly explains that cells sloughed (detached) from these tumors travel through the blood to distant sites and disrupt the normal functioning of other tissues, which is the definition and mechanism of metastasis.
Thus, both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

(B) Statement $(A)$ is incorrect because cancer cells have lost the property of contact inhibition,which allows them to continue dividing uncontrollably.
Statement $(B)$ is correct because benign tumors are non-cancerous and remain localized at their site of origin.
Statement $(C)$ is incorrect because metastasis is the most feared property of malignant tumors,not benign tumors.
Statement $(D)$ is correct because ionizing radiations like $X$-rays and gamma rays are physical carcinogens that cause $DNA$ damage,leading to neoplastic transformation.
Therefore,only statements $(B)$ and $(D)$ are correct.

(B) Metastasis is the most feared property of malignant tumors.
It refers to the process where cancer cells detach from the primary tumor,travel through the blood or lymphatic system,and invade distant parts of the body to form secondary tumors.
Benign tumors,on the other hand,remain confined to their original location and do not spread to other parts of the body.

(C) In normal cells,there are several genes known as $Proto-oncogenes$ (or cellular oncogenes).
These genes are present in an inactive state under normal physiological conditions.
When these genes are activated due to certain environmental factors,mutations,or viral infections,they transform into $oncogenes$.
These $oncogenes$ are responsible for the uncontrolled cell division and the cancerous transformation of cells.

(D) Sarcomas are cancers that arise from connective tissues,such as bone,cartilage,fat,muscle,or blood vessels.
$A$. Bone tumors (Osteosarcoma) are a type of sarcoma.
$B$. Cancer of cartilage (Chondrosarcoma) is a type of sarcoma.
$C$. Muscle tumors (e.g.,Rhabdomyosarcoma) are a type of sarcoma.
$D$. Cancer of lymph nodes is known as Lymphoma,which is a cancer of the lymphatic system,not a sarcoma.

(D) Neoplasms are abnormal growths of cells that form masses (tumors) and can invade surrounding tissues.
$A$,$B$,and $C$ (carcinoma,adenoma,and sarcoma) are types of solid tumors that form masses.
$D$ (leukemia) is a type of blood cancer characterized by the excessive production of white blood cells $(WBCs)$ in the bone marrow and blood.
Since leukemia does not form solid tumor masses that invade healthy tissues,it is the correct answer.

(B) Oncogenic viruses are viruses that have the ability to cause cancer in their host organisms.
$Epstein-Barr$ virus $(EBV)$,also known as human herpesvirus $4$,is a well-known oncogenic virus.
It is associated with the development of several types of cancers,including Burkitt's lymphoma,Hodgkin's lymphoma,and nasopharyngeal carcinoma.
Other options like Para influenza,Adenovirus,and $RSV$ are generally associated with respiratory infections rather than being primary oncogenic agents in humans.

(D) Leukopenia refers to a decrease in the number of white blood cells. In leukemia,there is an abnormal increase in the number of white blood cells,resulting in leukocytosis. Therefore,the statement that leukemia involves leucopenia is incorrect.

(C) Cancer is classified based on the tissue of origin.
$1$. Carcinoma refers to cancer of epithelial tissues.
$2$. Lymphoma refers to cancer of the lymphatic system.
$3$. Adenocarcinoma is a type of cancer that forms in glandular tissues. Since the pituitary gland is a major endocrine gland (glandular tissue),cancer arising from it is classified as an Adenocarcinoma.
$4$. Myosarcoma refers to cancer of muscle tissues.
Therefore,the correct option is $C$.