Ki-67 (MIB-1) is a marker of cell proliferation. A high value indicates a tumor that is proliferating more rapidly.

Ki-67 (MIB-1) is a Registry Data Collection Variable in AJCC. It is a new data item for cases diagnosed 1/1/2018+.

0.0-100.0	0.0 to 100.0 percent positive: enter percent positive
XXX.7	Test done, actual percentage not stated
XXX.8	Not applicable: Information not collected for this case (If this item is required by your standard setter, use of code XXX.8 will result in an edit error.)
XXX.9	Not documented in medical record Ki-67 (MIB-1) not assessed or unknown if assessed

Each Site-Specific Data Item (SSDI) applies only to selected primary sites, histologies, and years of diagnosis. Depending on applicability and standard-setter requirements, SSDIs may be left blank.