Q.1 Which type of gene, when mutated, can lead to uncontrolled cell division and cancer?
Oncogene
Tumor suppressor gene
Housekeeping gene
Proto-oncogene
Explanation - Oncogenes are mutated forms of proto-oncogenes that drive excessive cell proliferation, leading to cancer.
Correct answer is: Oncogene
Q.2 The TP53 gene is best known for encoding which protein?
p53
BRCA1
RAS
HER2
Explanation - TP53 encodes p53, a tumor suppressor protein that regulates the cell cycle and induces apoptosis in damaged cells.
Correct answer is: p53
Q.3 Which genetic mutation is commonly associated with hereditary breast and ovarian cancer?
BRCA1/BRCA2
KRAS
TP53
MYC
Explanation - Mutations in BRCA1 and BRCA2 genes impair DNA repair mechanisms, increasing susceptibility to breast and ovarian cancers.
Correct answer is: BRCA1/BRCA2
Q.4 Which type of mutation involves a single nucleotide change that creates a premature stop codon?
Nonsense mutation
Missense mutation
Frameshift mutation
Silent mutation
Explanation - A nonsense mutation introduces a stop codon in the coding sequence, leading to a truncated, nonfunctional protein.
Correct answer is: Nonsense mutation
Q.5 The Philadelphia chromosome results from a translocation between which chromosomes?
9 and 22
8 and 14
15 and 17
11 and 22
Explanation - The t(9;22)(q34;q11) translocation creates the BCR-ABL fusion gene, commonly found in chronic myeloid leukemia.
Correct answer is: 9 and 22
Q.6 Which gene family is primarily responsible for promoting cell cycle progression when mutated in cancer?
RAS family
TP53 family
BRCA family
CDKN family
Explanation - Mutations in RAS genes lead to constitutive activation of signaling pathways that drive uncontrolled cell proliferation.
Correct answer is: RAS family
Q.7 Which tumor suppressor gene is associated with Li-Fraumeni syndrome?
TP53
RB1
APC
PTEN
Explanation - Li-Fraumeni syndrome is caused by germline mutations in TP53, predisposing individuals to multiple cancers.
Correct answer is: TP53
Q.8 What type of mutation is most likely to activate a proto-oncogene?
Gain-of-function
Loss-of-function
Silent mutation
Frameshift deletion
Explanation - Gain-of-function mutations convert proto-oncogenes into oncogenes, promoting uncontrolled growth.
Correct answer is: Gain-of-function
Q.9 Which gene is most commonly mutated in colorectal cancers?
APC
BRCA2
KRAS
TP53
Explanation - Mutations in the APC gene disrupt Wnt signaling, leading to abnormal cell proliferation in the colon.
Correct answer is: APC
Q.10 Which epigenetic change is commonly observed in cancer cells?
DNA hypermethylation of tumor suppressor genes
Increased telomerase shortening
Increased histone acetylation globally
Loss of all mutations
Explanation - Hypermethylation silences tumor suppressor genes, contributing to cancer development.
Correct answer is: DNA hypermethylation of tumor suppressor genes
Q.11 Knudson’s two-hit hypothesis is used to explain the development of which type of cancers?
Retinoblastoma
Leukemia
Melanoma
Lung cancer
Explanation - The two-hit hypothesis suggests that both alleles of a tumor suppressor gene must be inactivated for tumor development.
Correct answer is: Retinoblastoma
Q.12 Which gene is associated with familial adenomatous polyposis (FAP)?
APC
TP53
RB1
KRAS
Explanation - Mutations in the APC gene lead to multiple colorectal polyps and increased risk of colorectal cancer.
Correct answer is: APC
Q.13 Which viral infection is strongly associated with cervical cancer?
Human papillomavirus (HPV)
Hepatitis B virus
Epstein-Barr virus
HIV
Explanation - HPV integrates into host DNA and expresses oncogenic proteins E6 and E7 that inactivate p53 and Rb.
Correct answer is: Human papillomavirus (HPV)
Q.14 Which protein complex is commonly overexpressed in breast cancer and is a target for monoclonal antibody therapy?
HER2/neu
TP53
KRAS
APC
Explanation - HER2 is a receptor tyrosine kinase; its overexpression promotes tumor growth and is targeted by drugs like trastuzumab.
Correct answer is: HER2/neu
Q.15 Which type of mutation is most likely responsible for inactivating a tumor suppressor gene?
Loss-of-function mutation
Gain-of-function mutation
Silent mutation
Synonymous mutation
Explanation - Loss-of-function mutations disable tumor suppressor genes, allowing unchecked cell proliferation.
Correct answer is: Loss-of-function mutation
Q.16 Which hereditary cancer syndrome is linked to mutations in mismatch repair genes?
Lynch syndrome
Li-Fraumeni syndrome
Familial adenomatous polyposis
Retinoblastoma
Explanation - Mutations in mismatch repair genes like MLH1 and MSH2 increase the risk of colorectal and other cancers.
Correct answer is: Lynch syndrome
Q.17 Which of the following is a hallmark of cancer cells?
Sustained proliferative signaling
Decreased glucose uptake
Enhanced apoptosis
Stable genome
Explanation - Cancer cells continuously activate pathways that promote proliferation, bypassing normal growth controls.
Correct answer is: Sustained proliferative signaling
Q.18 Which gene encodes a protein that inhibits cyclin-dependent kinases and is often mutated in cancers?
CDKN2A
KRAS
HER2
BRCA1
Explanation - CDKN2A encodes p16, which inhibits cyclin-dependent kinases; its inactivation allows unchecked cell cycle progression.
Correct answer is: CDKN2A
Q.19 Which chromosomal abnormality is frequently seen in Burkitt lymphoma?
t(8;14)
t(9;22)
t(15;17)
t(11;22)
Explanation - The t(8;14) translocation places MYC under the control of the immunoglobulin heavy chain promoter, driving proliferation.
Correct answer is: t(8;14)
Q.20 Which of the following is an example of an oncogene?
MYC
TP53
RB1
APC
Explanation - MYC is a proto-oncogene that, when mutated or overexpressed, promotes cell proliferation and cancer development.
Correct answer is: MYC
Q.21 Which tumor suppressor gene is linked to retinoblastoma?
RB1
TP53
BRCA1
KRAS
Explanation - RB1 encodes the retinoblastoma protein, which controls the G1-S checkpoint of the cell cycle; loss leads to tumor development.
Correct answer is: RB1
Q.22 Which mechanism allows cancer cells to evade apoptosis?
Overexpression of BCL-2
Activation of TP53
Mutation in KRAS
Deletion of HER2
Explanation - BCL-2 inhibits mitochondrial apoptosis pathways, allowing cancer cells to survive longer.
Correct answer is: Overexpression of BCL-2
Q.23 Which genetic event leads to chronic myeloid leukemia (CML)?
BCR-ABL fusion
BRCA1 mutation
KRAS activation
TP53 deletion
Explanation - The BCR-ABL fusion protein has constitutive tyrosine kinase activity, driving uncontrolled myeloid proliferation.
Correct answer is: BCR-ABL fusion
Q.24 Which of the following best describes a proto-oncogene?
A normal gene that can become an oncogene if mutated
A tumor suppressor gene
A DNA repair gene
A viral gene causing cancer
Explanation - Proto-oncogenes regulate normal cell growth but can become oncogenes when gain-of-function mutations occur.
Correct answer is: A normal gene that can become an oncogene if mutated
Q.25 Which gene mutation is commonly involved in pancreatic cancer?
KRAS
TP53
RB1
APC
Explanation - KRAS mutations are early events in pancreatic ductal adenocarcinoma and promote cell proliferation.
Correct answer is: KRAS