What describes the process when cancer cells break apart from each other?

The process when cancer cells break apart from each other is best described by metastasis. This term specifically refers to the spread of cancer cells from the original (primary) tumor to other parts of the body, where they can form secondary tumors. During metastasis, cancer cells invade surrounding tissues, enter the bloodstream or lymphatic system, and establish new sites of growth in different organs.

Neoplasia refers to the process of abnormal and uncontrolled cell growth, which may or may not be cancerous. Immortality, in the context of cancer cells, pertains to their ability to divide indefinitely without undergoing normal cellular aging and death, contributing to the persistence and growth of tumors. Contact inhibition is a process where normal cells stop dividing when they come into contact with other cells, but cancer cells typically lose this ability, allowing them to continue proliferating even when they are crowded together. Thus, while neoplasia, immortality, and contact inhibition are related to the behavior and characteristics of cancer cells, it is metastasis that specifically describes their ability to break apart and spread to other sites.