In which condition are cyclin and CDK levels often altered?

Cyclins and cyclin-dependent kinases (CDKs) play crucial roles in regulating the cell cycle, ensuring that cells progress through various phases in a controlled manner. In cancer cells, the regulation of these proteins is often disrupted.

Cancer cells may exhibit abnormal levels of cyclins or CDKs, leading to uncontrolled cell division. This dysregulation can occur due to mutations in genes that code for cyclins or CDKs, changes in the expression of these proteins, or alterations in the pathways that regulate their activity. As a result, cancer cells can bypass the normal checkpoints of the cell cycle, contributing to the rapid proliferation characteristic of tumors. This alteration in the levels and activity of cyclins and CDKs is a hallmark of many types of cancer, emphasizing the relationship between cell cycle regulation and cancer development.

In contrast, during normal cell function, cyclin and CDK levels are typically regulated in a coordinated manner to ensure proper cell cycle progression. The situation is similar during mitosis only, as cyclins and CDKs are specifically involved at various points throughout the entire cell cycle, rather than being limited to one phase. Furthermore, while cyclins and CDKs can respond to environmental changes, this response does not capture the specific alteration associated with