The scale goes from I to IV based on the morphologic and functional features of the tumor cells; a grade IV tumor being the most abnormal looking cells that also tend to be the most aggressive.

基细胞的形态和功能特征，分从I级到IV级；细胞形态最异常的IV级也往往最有侵袭性。

Pathology as a medical specialty is the branch of medicine that deals with the study of diseases and the morphologic, physiologic changes produced by them.

病理一种医专业是涉及疾病的研究和它们产生的形态，生理变化的医分支。