Malignant cells are cancerous cells characterized by uncontrolled growth, the ability to invade surrounding tissues, and often, the capability to spread (metastasize) to distant organs through the bloodstream or lymphatic system.
They originate from normal cells that have undergone genetic mutations that affect their growth and differentiation. These mutations can be caused by a variety of factors, including exposure to carcinogens like tobacco smoke or UV radiation, certain viral infections, inherited genetic mutations, or simply errors that occur during DNA replication.
Here are some key characteristics of malignant cells:
- Uncontrolled growth and proliferation: Unlike normal cells, malignant cells do not respond to the usual signals that regulate cell division. As a result, they divide and grow uncontrollably, forming a mass of cells called a tumor.
- Immortality: Normal cells can only divide a certain number of times before they become senescent and stop dividing. In contrast, malignant cells often have the ability to divide indefinitely, a trait known as immortality.
- Invasion and metastasis: Malignant cells can invade nearby tissues and break away from the original tumor to spread to other parts of the body, a process known as metastasis. This ability to spread distinguishes malignant tumors from benign tumors, which can grow but do not invade other tissues or spread to distant sites.
- Angiogenesis: Malignant cells can stimulate the formation of new blood vessels to supply the tumor with nutrients, a process known as angiogenesis.
- Avoidance of immune destruction: Malignant cells can evade the immune system, which normally recognizes and destroys abnormal cells, through various mechanisms.
- Genetic instability: Malignant cells often have a higher rate of genetic mutations compared to normal cells, which can drive further changes in their behavior.
Because of their unique characteristics, malignant cells require specific strategies for treatment, including surgery, radiation therapy, chemotherapy, immunotherapy, and targeted therapies that are designed to interfere with specific pathways involved in cancer growth and progression.
