What characterizes malignant cells?

Malignant cells are characterized by uncontrolled reproduction and their immortal nature. This means that they proliferate rapidly and do not respond to the normal regulatory signals that typically limit cell division. Unlike normal cells, which follow a controlled growth pattern and undergo programmed cell death (apoptosis), malignant cells can divide indefinitely, leading to tumor formation and cancer progression.

This relentless growth is often driven by genetic mutations that enable them to bypass the usual checkpoints of the cell cycle, contributing to their ability to proliferate uncontrollably. Additionally, malignant cells often develop mechanisms to evade the immune system and resist treatments, further differentiating them from healthy tissue, which is subject to regulation and homeostasis.

The other answer choices highlight characteristics typical of normal cells or benign growth, which are not applicable to malignant cells. Hence, the feature of uncontrolled reproduction and immortality distinctly characterizes malignant cells and is central to understanding tumor biology and cancer treatment strategies.