Tumor grade refers to how much the cancer cells differ from normal cells under a microscope, and it provides information about how aggressively the tumor is likely to behave. ๐Ÿง  What does tumor grade indicate? Tumor grade describes the appearance and behavior of cancer cellsโ€”how abnormal they look and how quickly they are likely to grow and spread. ๐Ÿ” Grading Criteria (Microscopic evaluation): Cell differentiation โ€“ How closely cancer cells resemble the normal cells of the same tissue. Nuclear atypia โ€“ Abnormal size, shape, and structure of cell nuclei. Mitotic rate โ€“ How frequently the cells are dividing. Necrosis โ€“ Presence of dead tumor cells (in some grading systems). ๐Ÿ“Š Common Tumor Grades: Grade 1 (Low grade): Well-differentiated cells; resemble normal cells; slow-growing. Grade 2 (Intermediate grade): Moderately differentiated; more abnormal; moderately aggressive. Grade 3 (High grade): Poorly differentiated or undifferentiated; very abnormal; fast-growing and more likely to spread. ๐Ÿงฌ Examples of Specific Grading Systems: Gleason Score (for prostate cancer) Bloom-Richardson Grade (for breast cancer) WHO CNS Tumor Grades (for brain tumors, Grade I to IV) Would you like the tumor grade definition adapted for a specific tumor type (e.g. glioma, breast cancer)?