Hematoxylin and eosin stains from different sections of a single diffuse intrinsic pontine glioma specimen, showing low-grade (top) and high-grade (bottom) areas. In pathology,<unk> is a measure of the cell appearance in tumors and other neoplasms. Some pathology<unk> systems apply only to malignant neoplasms (cancer); others apply also to benign neoplasms. The neoplastic<unk> is a measure of cell anaplasia (reversion of differentiation) in the sampled tumor and is based on the resemblance of the tumor to the tissue of origin.<unk> in cancer is distinguished from staging, which is a measure of the extent to which the cancer has spread. Pathology<unk> systems classify the microscopic cell appearance abnormality and deviations in their rate of growth with the goal of predicting developments at tissue level (see also the 4 major histological changes in dysplasia). Cancer is a disorder of cell life cycle alteration that leads (non-trivially) to excessive cell proliferation rates, typically longer cell lifespans and poor differentiation. The grade score (numerical: G1 up to G4) increases with the lack of cellular differentiation - it reflects how much the tumor cells differ from the cells of the normal tissue they have originated from (see 'Categories' below). Tumors may be graded on four-tier, three-tier, or two-tier scales, depending on the institution and the tumor type. The histologic tumor grade score along with the metastatic (whole-body-level cancer-spread) staging are used to evaluate each specific cancer patient, develop their individual treatment strategy and to predict their prognosis. A cancer that is very poorly differentiated is called anaplastic.
Grading 
Staining
Chemical nomenclature
Phenotype 
Latch 
Presentation 
Four Score
Hair analysis