Which characteristic describes cancer cells' ability to grow without the presence of growth factors?

The ability of cancer cells to grow without the presence of growth factors is best characterized by growth factor independence. In normal physiology, cells rely on growth factors to signal them to divide and grow. These factors are typically proteins that bind to receptors on the cell surface, triggering a cascade of cellular responses that result in cell proliferation.

However, cancer cells often acquire mutations that allow them to bypass these external growth signals. This means they can continue to proliferate even in the absence of growth factors, contributing to their uncontrolled growth and survival characteristics that are hallmark traits of cancer. This independence from growth factors allows cancer cells to thrive in conditions where normal cells would either stop growing or die off due to lack of necessary signals.

The other options describe different characteristics of cell behavior. Cell density-dependent inhibition refers to the phenomenon where cell growth is inhibited once a certain density is reached, which is typically observed in normal cells but not in cancer cells. Cell-to-cell communication involves signaling between cells for coordination and regulation, a process that can be disrupted in cancer. Anchorage dependence describes the requirement of normal cells to attach to a surface to grow, which cancer cells often circumvent, allowing them to grow unattached in various environments. These characteristics further highlight the abnormal behaviors of cancer cells compared to