Which of the following indicates a lack of differentiation in cancer cells?

Anaplasia refers specifically to the loss of differentiation in cancer cells. It is characterized by cells that have reverted to a more primitive, undifferentiated state. This means that the cancer cells no longer have the specialized features typical of their tissue of origin. As a result, anaplastic cells tend to appear abnormal in size, shape, and arrangement, making it difficult to determine their tissue of origin under a microscope.

Differentiation in cancer typically reflects how much the cancer cells resemble normal cells in the tissue from which they arise, regarding both structure and function. Anaplastic cells, due to their lack of differentiation, usually indicate a more aggressive tumor that may correlate with a poorer prognosis.

Other choices relate to cellular changes but do not indicate a complete loss of differentiation like anaplasia does. Metaplasia involves one type of adult cell being replaced by another type suitable for the environment, while dysplasia indicates abnormal cell growth or development but often retains some degree of differentiation. Morbidity, on the other hand, refers to the state of being diseased or the presence of complication in health and does not directly pertain to cellular differentiation.