Invasion

Synonyms

Infiltration; Tumor cell invasion

Definition

Is a process in malignant cells consisting of penetration of and movement through surrounding tissues.

Characteristics

Following an initial period of cell proliferation at the tissue site of origin, malignant cells acquire the capacity to undergo invasion of the surrounding tissues. Some malignant neoplasms undergo extensive local invasion without metastasizing, but invasion is a prerequisite for the development of metastasis.

Although the process is not the same for all types of malignancies, the invasion of epithelial-derived malignant cells (the most common type) involves the following steps (Fig. 1):

• Detachment from adjacent cells and underlying basement membrane

• Disruption and degradation of surrounding matrix

• Adhesion to surrounding matrix components

• Migration through the adjacent tissue

Fig. 1

Schematic representation of the steps involved in tumor cell invasion