Genetic Basis of Cancer Quiz

Cancer is characterized by uncontrolled cell division.

Oncogenes promote cell division, while tumor-suppressor genes inhibit cell division.

A metastatic cancer has spread to a different site in the body.

<p>Most cancers originate from a single cell that undergoes genetic mutations.</p> Signup and view all the answers

<p>They damage DNA and induce mutations that can lead to cancer.</p> Signup and view all the answers

<p>Tumor viruses are capable of directly causing cancer in various species, including humans.</p> Signup and view all the answers

<p>A benign growth is a non-invasive tumor that has not yet become cancerous.</p> Signup and view all the answers

<p>Human Papillomavirus (HPV) is associated with causing cervical cancer.</p> Signup and view all the answers

<p>Epstein-Barr virus is a causative agent of Burkitt lymphoma, particularly in immunosuppressed individuals like AIDS patients.</p> Signup and view all the answers

<p>Approximately 80% of human cancers are not induced by viruses.</p> Signup and view all the answers

<p>Oncogenes induce cell transformation and promote uncontrolled cell proliferation, leading to cancer.</p> Signup and view all the answers

<p>A proto-oncogene is a normal gene that, when mutated, can lead to cancer by promoting uncontrolled cell growth.</p> Signup and view all the answers

<p>Tumor suppressor genes inhibit cell proliferation and tumor development, acting as a safeguard against cancer.</p> Signup and view all the answers

<p>The Rb gene was the first tumor suppressor gene identified and is crucial for understanding retinoblastoma inheritance.</p> Signup and view all the answers

<p>p53 acts as a negative regulator of the cell cycle and induces apoptosis in response to DNA damage.</p> Signup and view all the answers

<p>Oncogenes promote cell growth and proliferation, while tumor suppressor genes inhibit these processes.</p> Signup and view all the answers

<p>Rb inhibits progression past the restriction point in G1 by remaining in its active form until it is phosphorylated by Cdk4,6/cyclin D complexes.</p> Signup and view all the answers

<p>p16 inhibits the activity of Cdk4,6/cyclin D complexes, thus preventing the phosphorylation and inactivation of Rb.</p> Signup and view all the answers

<p>Wild-type p53 is crucial for inducing cell cycle arrest through p21 and triggering apoptosis via proapoptotic proteins like PUMA and Noxa.</p> Signup and view all the answers

<p>Oncogenes are mutated genes that promote cancerous growth, while tumor suppressor genes prevent the formation of cancer.</p> Signup and view all the answers

<p>Loss-of-function in a tumor suppressor gene allows unregulated cell growth and can lead to cancer development.</p> Signup and view all the answers

<p>A gain-of-function mutation may increase the amount of protein produced by the proto-oncogene.</p> Signup and view all the answers

<p>Mutations in ras genes, which are proto-oncogenes, lead to a constitutively active Ras protein that promotes cell division.</p> Signup and view all the answers

<p>One type of mutation is a missense mutation, resulting in a change to an amino acid that alters protein function.</p> Signup and view all the answers

<p>Pro-apoptotic Bcl-2 family members like PUMA and Noxa promote apoptosis; their induction may be compromised in cancer, allowing cells to evade death.</p> Signup and view all the answers

<p>p16 negatively regulates cyclin-dependent kinases, controlling the transition from the G1 phase to the S phase of the cell cycle.</p> Signup and view all the answers

<p>NF1 stimulates Ras to hydrolyze its GTP to GDP, and loss of NF1 function leads to overactivity of Ras, promoting cell division.</p> Signup and view all the answers

<p>APC is a negative regulator of a signaling pathway that activates genes promoting cell division.</p> Signup and view all the answers

<p>p53 acts as a checkpoint sensor of DNA damage, regulating target genes to prevent cell cycle advancement or promote apoptosis.</p> Signup and view all the answers

<p>BRCA1 and BRCA2 facilitate DNA repair processes and can promote apoptosis if the damage is irreparable.</p> Signup and view all the answers

<p>Tumor-suppressor genes are categorized into those that negatively regulate cell division and those that maintain genome integrity.</p> Signup and view all the answers

<p>Epigenetics studies heritable traits that change cell function without altering the DNA sequence.</p> Signup and view all the answers

<p>Checkpoint proteins detect genetic abnormalities and prevent the division of cells until issues are resolved.</p> Signup and view all the answers

<p>A missense mutation is a change in a DNA sequence that results in the substitution of one amino acid for another in a protein. This can alter the function of tumor-suppressor genes, potentially leading to uncontrolled cell division and cancer.</p> Signup and view all the answers

<p>Gene amplification is the process by which a cell increases the number of copies of a particular gene. This can lead to overexpression of proteins that may promote cell division, contributing to cancer progression.</p> Signup and view all the answers

<p>Chromosomal translocation involves the rearrangement of parts between nonhomologous chromosomes, which can lead to the formation of oncogenes or disrupt tumor-suppressor genes. This can result in abnormal cell growth and cancer.</p> Signup and view all the answers

<p>When tumor-suppressor genes lose their function, the regulation of cell division is impaired, leading to unrestrained cell proliferation and increased cancer risk. This loss can occur through mutations, deletions, or other genetic alterations.</p> Signup and view all the answers

<p>The Rb protein inhibits the transcription factor E2F, which activates genes necessary for cell cycle progression. By binding to E2F, Rb prevents cells from advancing through the cell cycle.</p> Signup and view all the answers

<p>The two-hit model posits that retinoblastoma requires two mutations: inherited forms start with one mutation, while non-inherited forms require two mutations occurring later in life. Both scenarios lead to tumor development.</p> Signup and view all the answers

<p>The p53 protein primarily acts as a guardian of the genome by detecting DNA damage and activating pathways for DNA repair, cell cycle arrest, or apoptosis. Its dysfunction can contribute to cancer progression.</p> Signup and view all the answers

<p>Apoptosis is a programmed cell death process that removes damaged or unwanted cells through specific morphological changes, vital for maintaining cellular health and preventing tumorigenesis. Failure of apoptosis can lead to tumor growth.</p> Signup and view all the answers

<p>The two main categories of tumor-suppressor genes are those that negatively regulate cell division and those that are involved in DNA repair mechanisms. Both are essential for preventing cancer.</p> Signup and view all the answers

<p>Viral integration can lead to the insertion of viral oncogenes into host cell genomes, potentially inactivating tumor-suppressor genes or activating oncogenes. This disruption can result in uncontrolled cell growth and cancer.</p> Signup and view all the answers

<p>DNA methylation and histone modification are epigenetic changes that alter gene expression without modifying the DNA sequence, whereas mutations involve changes to the nucleotide sequence.</p> Signup and view all the answers

<p>Epigenetic changes can directly contribute to disease symptoms by altering gene expression patterns related to the disease.</p> Signup and view all the answers

<p>Mutations can lead to either inhibition or increased function of chromatin-modifying proteins, significantly affecting gene expression.</p> Signup and view all the answers

<p>Colorectal cancer and breast cancer are commonly associated with mutations in histone acetyltransferase.</p> Signup and view all the answers

<p>Environmental agents can alter the functions of chromatin-modifying proteins, potentially leading to epigenetic changes that are associated with cancer.</p> Signup and view all the answers

<p>Polycyclic aromatic hydrocarbons are environmental agents that can cause epigenetic changes associated with multiple cancer types, including lung and breast cancer.</p> Signup and view all the answers

<p>5-azacytidine is a drug being researched for its ability to inhibit DNA methylation in cancer cells.</p> Signup and view all the answers

<p>The SWI/SNF complex alters the positions of histones, influencing the accessibility of DNA for transcription.</p> Signup and view all the answers

<p>Histone demethylase removes methyl groups from histones, potentially leading to abnormal gene expression patterns associated with cancers such as multiple myeloma.</p> Signup and view all the answers

<p>Epigenetic changes may be indirect if a third factor, such as a toxic agent, influences both the disease and the epigenetic alterations.</p> Signup and view all the answers

<p>Increased function of chromatin-modifying proteins can lead to enhanced gene expression and contribute to oncogenesis.</p> Signup and view all the answers

<p>Research can identify this association through the observation of specific epigenetic changes in cancer cells and their correlation with clinical outcomes.</p> Signup and view all the answers

<p>Histone phosphorylation can influence gene expression by altering chromatin structure, which is associated with cancers like medulloblastoma.</p> Signup and view all the answers

<p>Disease symptoms may arise first, leading to cellular stress that triggers epigenetic alterations as an adaptive response.</p> Signup and view all the answers