High-grade Serous Carcinoma : Immunostains
The immunohistochemical profile of ovarian cancers in general is as follows:
- CK7 positive/CK20 negative
- Positive for CK8, CK18, CK19, EMA, B72.3, S-100 protein (borderline tumors), PAX8 and p16
- PAX2 : positive (nuclear staining) in borderline serous tumors and low-grade serous carcinomas; usually negative in high-grade serous carcinomas.
- Positive for ER, PR, and AR
- P53 : More than 90% of high-grade serous carcinomas harbor TP53 mutations which can be detected immunohistochemically as strong nuclear positivity for p53 (missense mutation) OR as complete lack of staining in any tumor cell nuclei (nonsense mutation resulting in truncated protein that cannot be detected by the p53 antibody.
- Occasionally positive for vimentin, GFAP, beta-hCG, calretinin, inhibin, and TTF-1
- WT1 is diffusely positive in most high-grade ovarian serous carcinomas. This is helpful in differentiating them from other ovarian tumors such as endometrioid and clear cell carcinomas as well as uterine papillary serous carcinomas where WT1 is negative.
- Important NEGATIVE markers of serous tumors: CK20, CEA, CDX-2