NCERT · Class 12 · Biology · Human Health and DiseasesWhat is Metastasis? In which type of tumor is it predominantly observed?

Metastasis is the most feared and distinctive property of malignant tumors (cancerous tumors). It refers to the process in which cancerous cells slough off or detach from the primary site of origin, enter the circulatory or lymphatic stream, and travel to distant organs and tissues of the body. Upon reaching new sites, these cells lodge, proliferate, and initiate the formation of secondary tumors. Benign tumors do not show metastasis as they remain confined to their original locations and do not spread to other body parts.