Cancer- (biol465) Quiz

ErbB2 mutations can be especially helpful to cancer cells because they interact with Ras, a commonly mutated protein, resulting in increased signaling pathways that promote cancer cell growth and proliferation.

Ink4A/B functions by inhibiting cyclin 4A and 4B, similar to p15/p16, and its relationship to p53 is a key aspect of its function in cell cycle regulation.

Smad4 downstream effects involve promoting transcription of p15/p16 and inhibiting plasminogen activator to prevent breakdown of connective tissue. The incorrect answers do not correspond to the known functions of Smad4.

The correct pathway for upstream signalling effectors that affect Smad4 involves TGF B receptors activating Smad3, which then activates Smad4 leading to Smad4 phosphorylation.

TGF B is known to positively regulate Ink4a/b production, which plays a key role in cell cycle regulation and tumor suppression.

In cancer, various changes can occur in proteins involved in the cell cycle regulation. The correct changes associated with cancer development are loss of Ink4's or Rb2, mutation of CDK4 impairing its interaction with p16, and overexpression of CyclinD. The incorrect answers provided deviate from the correct changes observed in cancer cells.

Thelper cells are known to display CD4+ markers on their surface, which helps in identifying them as a subtype of T cells. CD8+ is typically found on cytotoxic T cells, CD3+ is a general marker of T cells, and CD16+ is found on natural killer cells.

The correct answer is Macrophages because they play a crucial role in surveilling and destroying cancer cells in the body. NK cells, B cells, and Neutrophils also play a role in the immune response against cancer, but macrophages are specifically known for their direct interaction with Thelper cells in recognizing and targeting cancer cells.

Innate immune cells have receptors that are sensitive to changes in shape, allowing them to detect pathogenic antigens or damage or danger. The incorrect answers provided do not align with the function of innate immune cell receptors.

E2F is a transcription factor that plays a crucial role in activating the transcription of genes required for DNA synthesis, making it essential for cell cycle progression and cell proliferation.

Rb primarily binds to E2F transcription factor to regulate the cell cycle by repressing the expression of proteins required for DNA synthesis.

p16 functions by inhibiting the activity of CyclinD/CDK4 which prevents the release of E2F from Rb, leading to cell cycle arrest.

CD8+ cells, also known as T Cytotoxic lymphocytes (Tc Cells), are a subset of T cells that play a key role in cell-mediated immunity by directly killing infected or abnormal cells. B Cells, Natural Killer Cells, and Macrophages do not express CD8 markers and have different functions in the immune system.

CD4+ cells release cytokines to signal other immune cells in the immune response cascade. This allows for the coordinated attack on aberrant cells and pathogens.

Cancer immunoediting is a complex process involving the immune system's surveillance and elimination of abnormal cells to prevent tumor growth.

Tcell infiltration is typically associated with a favourable prognosis as long as the response is resolved. This is due to the immune system's ability to target and eliminate potentially harmful cells. In contrast, poor prognosis, no impact on prognosis, or unpredictable outcomes are not commonly linked with Tcell infiltration.

The correct answer involves immune cells that can induce apoptosis in cancer cells through the Fas signalling pathway. The incorrect answers do not directly activate the Fas pathway in cancer cells.

The evasion of apoptosis involves mechanisms that promote cell survival and inhibit programmed cell death. Upregulation of pro-apoptotic proteins, activation of caspase enzymes, and maintenance of healthy mitochondria are not mechanisms associated with evading apoptosis. In fact, these processes would typically promote apoptosis rather than inhibit it.

Proapoptotic proteins within the Bcl2 protein family promote cell death by activating pathways leading to apoptosis. Bax, Bad, and Bid are examples of such proteins, while Bcl2 itself is an antiapoptotic protein. Bim and Puma are also proapoptotic proteins but do not belong to the Bcl2 protein family.

The Bcl2 protein family consists of various proteins involved in regulating apoptosis (cell death). Among the antiapoptotic proteins in this family, some examples include Bcl-2, Bcl-xL, Bcl-w, and Bcl-B. These proteins play a critical role in preventing cell death by blocking the activation of proapoptotic proteins.

In the absence of a trophic factor, apoptosis in a normal cell is initiated through the activation of caspases in a cascade, ultimately leading to cell death through a series of well-defined steps.

p53 plays a critical role in regulating cell growth and preventing tumor formation by inducing growth arrest, DNA repair, and apoptosis. It does not directly control cell division, protein synthesis, or energy metabolism.

Viral oncoproteins can interact with p53 in various ways, leading to inhibition of its function or mutations. The incorrect answers provided do not accurately depict the known interactions between viral oncoproteins and p53.

p53 is a tumor suppressor gene that is commonly inactivated in colon cancer, leading to unchecked cell growth. While p53 mutations can also occur in breast, lung, and prostate cancers, they are not as universally present as in colon cancer.

p53 acts as the 'Guardian of the Genome' by monitoring cell division and initiating apoptosis in cells with damaged DNA to prevent the replication of mutations, ensuring genomic stability.

DNA damage triggers the stabilization of p53, allowing it to accumulate and function as a negative regulator of growth to prevent damaged cells from proliferating uncontrollably.