Tumor differentiation is assessed through histopathological examination. A tissue sample or biopsy from the tumor is stained and examined under a microscope by a pathologist. The pathologist evaluates various characteristics such as cell shape, size, structure, and organization. They also look at the presence of mitotic figures, nuclear atypia, and the architectural pattern of the tissue. Based on these observations, the tumor is classified into well-differentiated, moderately-differentiated, poorly-differentiated, or undifferentiated.
