Cancer can be judged according to the degree of cell differentiation combined with the depth of tumor infiltration and the size of the primary tumor and the presence of metastasis, as follows: 1. Cancer cells can be divided into undifferentiated cancer, low differentiated cancer, middle differentiated cancer and highly differentiated cancer, poorly differentiated may be low differentiated and undifferentiated cancer, which is more malignant and most of them belong to stage III or stage IV, but there is no way to fully judge the stage based on the degree of cell differentiation alone, it should be combined with the depth of tumor infiltration and the size of the primary tumor. If there is distant metastasis, most of them are stage IV. If there is no distant metastasis, imaging examination, including post-surgical pathology, is needed to determine the stage. The higher the degree of differentiation, the lower the degree of malignancy, so poorly differentiated tumors are generally more malignant.