IMMUNOHISTOCHEMISTRY: Ki-67

KI-67 IS A NUCLEAR PROTEIN PLAYING A PIVOTAL ROLE IN MAINTAINING CELL PROLIFERATION. KI-67 IS PRESENT IN ALL NON-G0 PHASES OF THE CELL CYCLE. BEGINNING IN THE MID-G1, THE LEVEL INCREASES THROUGH S AND G2 TO REACH A PEAK IN M PHASE. IN THE END OF M PHASE, IT IS RAPIDLY CATABOLIZED. KI-67 HAS BEEN EMPLOYED AS A MARKER OF PROLIFERATION AND HENCE, PROGNOSIS IN NEOPLASMS OF MANY TYPES SUCH AS MALIGNANT LYMPHOMAS, PROSTATIC AND BREAST ADENOCARCINOMAS, ASTROCYTIC NEOPLASMS AND SOFT TISSUE NEOPLASMS. KI-67 IS AN ESTABLISHED PROGNOSTIC BIOMARKER IN BREAST CANCER. IT IS WIDELY USED AS A MARKER OF PROLIFERATION.