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.

HER-2 OVEREXPRESSION IN BREAST CARCINOMA IS ASSOCIATED WITH SHORTER DISEASE FREE INTERVAL AND SHORTER OVERALL SURVIVAL. HER-2 POSITIVE BREAST CANCERS TEND TO BE MORE AGGRESSIVE BUT TREATMENTS THAT TARGET HER-2 ARE VERY EFFECTIVE. EXPRESSION OF HER-2 PROTEIN IS AN INDICATION FOR SPECIFIC THERAPY WITH TRASTUZUMAB / HERCEPTIN / PERTUZUMAB / NERATINIB IN PATIENTS WITH BREAST CANCER.

ESTROGEN RECEPTOR (ER) IS A STEROID HORMONE RECEPTOR COMMONLY USED ALONGWITH PROGESTERONE RECEPTOR (PR) IN THE MANAGEMENT OF WOMEN WITH BREAST CANCER. ER & PR STATUS PROVIDES AN INDICATION OF PROGNOSIS AND POTENTIAL BENEFIT FROM HORMONAL THERAPY. GENERALLY ER & PR POSITIVE TUMORS ARE MORE LIKELY TO RESPOND TO ENDOCRINE THERAPY AND HAVE A BETTER PROGNOSIS, STAGE FOR STAGE AS COMPARED TO RECEPTOR NEGATIVE TUMORS. THIS TEST IS ALSO RECOMMENDED FOR PATIENTS WITH DUCTAL CARCINOMA IN SITU (DCIS) TO PREDICT POTENTIAL BENEFIT OF ENDOCRINE THERAPIES.

PROGESTERONE RECEPTOR (PR) IS A SURROGATE MARKER OF ESTROGEN RECEPTOR (ER) ACTIVITY IN THE MANAGEMENT OF WOMEN WITH BREAST CANCER. ER & PR STATUS PROVIDES AN INDICATION OF PROGNOSIS AND POTENTIAL BENEFIT FROM HORMONAL THERAPY. GENERALLY ER & PR POSITIVE TUMORS ARE MORE LIKELY TO RESPOND TO ENDOCRINE THERAPY AND HAVE A BETTER PROGNOSIS, STAGE FOR STAGE AS COMPARED TO RECEPTOR NEGATIVE TUMORS. THIS TEST IS RECOMMENDED IN PATIENTS WITH NEWLY DIAGNOSED BREAST CANCER AND METASTATIC & RECURRENT BREAST CANCER.