Question

For each of the following categories, decide whether genes in that category are likely to be tumor-suppressor genes, oncogenes, or either one. Explain your answer. (Hint: think about whether the gene function would have to be lost (tumor-suppressor) or overactive/hyperactive (oncogene) to promote tumorigenesis. growth factor receptors

Answer 1

Growth factor receptors are likely to be categorized as oncogenes because their overactivity can promote cell division and lead to cancer. Tumor suppressor genes act as brakes to control cell growth, and loss of their function can also contribute to tumorigenesis.

Step-by-step explanation:

The function of growth factor receptors can help us decipher whether they are likely to be categorized as tumor suppressor genes or oncogenes. Growth factor receptors, when bound by their ligands, generally stimulate cell growth, proliferation, and differentiation. If these receptors become overactive, either through a gain of function mutation or through overexpression, they will continuously signal cells to divide and grow, even in the absence of the normal growth signals. This unregulated activity can lead to tumorigenesis, indicating that when mutated, growth factor receptors typically behave as oncogenes.

By contrast, tumor suppressor genes are more like brakes for the cell, preventing excessive division and ensuring repairs are made to DNA damage before division continues. If a tumor suppressor gene is mutated such that it loses its function, the cell division brake is off, leading to potential unchecked growth and cancer formation. Thus, the loss of function mutation occurring in a tumor suppressor gene contributes to cancer development.

Answer 2

Genes encoding growth factor receptors are likely to function as oncogenes when overactive or hyperactive. Amplification or overexpression of these receptors can lead to uncontrolled cell growth and division, promoting tumorigenesis.

Step-by-step explanation:

Growth factor receptors play a crucial role in cell signaling pathways that regulate cell growth, proliferation, and differentiation. When these receptors become overactive or hyperactive, it often results in an excess stimulation of downstream signaling pathways, leading to uncontrolled cell division and tumor formation.

In the context of oncogenes, mutations or alterations that enhance the activity of growth factor receptors can contribute to the development of cancer. For example, gene amplification or overexpression of the receptor can lead to increased signaling, promoting cell survival and proliferation.

Conversely, loss of function in growth factor receptors would not typically promote tumorigenesis. Tumor-suppressor genes usually require a loss-of-function mutation or deletion to contribute to cancer development. In the case of growth factor receptors, a decrease or loss of function would likely lead to decreased signaling, which could hinder normal cellular responses but may not necessarily drive uncontrolled cell growth.

Therefore, the likely scenario for growth factor receptors is that overactivity, rather than underactivity, contributes to their role as oncogenes in the context of cancer development. Understanding the specific functions of genes within different categories is crucial for elucidating their roles in cancer and developing targeted therapeutic interventions.