What characterizes malignant tumors in regard to growth?

Malignant tumors are characterized by a loss of substrate dependency, which refers to their ability to grow and proliferate without being anchored to a specific surface or in a particular location. This trait allows malignant cells to detach from their original site, facilitating invasion into surrounding tissues and metastasis to distant sites in the body.

In contrast, normal cells typically require attachment to a substrate to grow and survive. When cells become malignant, they often lose this requirement, enabling them to grow independently. This characteristic contributes to the aggressive nature of malignant tumors, making them more dangerous than benign tumors, which remain localized and usually retain substrate dependency.

Immortal cell division pertains to the ability of cancer cells to divide indefinitely, but it is not as definitive a characteristic of malignancy regarding growth patterns compared to the loss of substrate dependency. Normal tissue adherence is a quality found in healthy cells, which malignant cells lose in their transformation. Substrate dependency is also associated with normal cellular behavior, contrasting directly with the nature of malignant tumor growth. Understanding these concepts is crucial for recognizing how cancer spreads and behaves within the body.