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.

病理学作为一种医学专业是涉及疾病的研究它们生的学，生理学变化的医学分支。

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.

基于肿瘤细胞的功能特征，分为从I级到IV级；细胞最为异常的IV级肿瘤也往往最有侵袭性。