Cancer antigen 125 (CA125), which is encoded by MUC16, is the only biomarker currently used for immunohistochemical diagnosis of ovarian cancer (Tanyi and Scholler 1098). Literature suggests that 80% of the patients with ovarian cancer express CA125. The expression pattern is different among the different kinds of ovarian cancer; 85% in serous ovarian cancer, 12% in mucinous cancer and 40% in clear cell carcinoma (Tanyi and Scholler 1098; Kaspar and Crum 44), which helps in differential diagnosis.
Differential diagnosis among various types of ovarian cancer. There are five types of primary ovarian cancers, namely, high-grade serous carcinomas (HGSC) (70% occurrence rate), clear cell carcinoma (10%), endometrioid carcinomas (10%), mucinous carcinoma (3%) and low-grade serous carcinoma (less than 5%) (Prat 111). Ovarian serous cancer is WT1+, CK7+, CA125+ and CK20- (Waldstrøm and Grove 85), whereas such a profile is absent in metastasized carcinoma of the cervix, lungs and the breast to the ovary (Mittal et al. 402). Non-mucinous ovarian carcinomas are CK7 positive but negative for CK20 while primary ovarian mucinous tumors are strongly positive for CK7 and MUC5AC but weakly positive CK20 (Chu et al. 962; Prat 115). Endometrioid carcinomas are often associated with uterine cancer and are strongly positive for vimentin and CK7, weakly positive for CK20 and negative for CD56 (Prat 115). CCC are strongly positive for HNF1-β and negative for WT1 and ER (Köbel et al. 14; Kaspar and Crum 44), helping in distinguishing it from HGSC. Sex stromal cell carcinoma and germ cell carcinoma are rare forms of ovarian cancers. Germ cell carcinoma can be identified using Sal-like protein 4 (SALL4) (Rabban and Zaloudek 72), human chorionic gonadotrophin (HCG) and serum alpha-fetoprotein (AFP) (Tanyi and Scholler 1100) while sex stromal cell is positive for CD56, calretinin and inhibin but negative for epithelial membrane antigen (EMA). Dysgerminoma, a common form of germ cell cancer is often identified using OCT4, CD117, D2-40 and SALL4 (Mittal et al. 404; Deavers et al. 576; Kaspar and Crum 44; Rabban and Zaloudek 73).
Differential diagnosis of metastasized cancer to the ovary. Primary ovarian cancer is strongly positive for cytokeratin 7 (CK7) (Deavers et al. 574; Heatley 270; Kaspar and Crum 44), Wilms tumor protein (WT1), estrogen receptors (ER), progesterone receptors (PR) (Mittal et al. 402) and CA125. This biomarker panel is useful in differential diagnosis of primary ovarian cancer from metastasized breast cancer (GCDFP-15+, vimentin-), gastric carcinoma (ER-, PR-, CK7+, weak CK20+), colorectal cancer (strong CK7+, β-catenin+, MUC5AC-), renal cancer (CD10+), cervical cancer (ER+, PR+, p16+, CA125-), mesothelioma (Calretinin+, thrombomodulin+, keratin 5/6+) and pancreatic cancer (CA 19-9+) (Heatley 269; Mittal et al. 404).
Summary. A biomarker panel containing CK7, ER, PR, WT1, CA125, vimentin, calretinin, inhibin, HNF1-β, HCG, AFP and SALL4 could be used along with markers such as GCDFP-15, p16, β-catenin and CA 19-9 for adequate diagnosis and differential diagnosis of ovarian cancer.
Immunohistochemical markers in cervical malignancies
Cervical lesions are usually identified using traditional histopathological studies using hematoxylin and eosin staining (Wentzensen and von Knebel Doeberitz 316). High grade or low grade SIL (HSIL or LSIL, respectively) is preceded by three stages of cervical intraepithelial neoplasia (CIN) (Adekunle 279). CIN may or may not develop into cancerous lesions. Another classification suggests that LSIL are benign while HSIL have greater potential to develop into squamous cell carcinoma of the cervix and are often associated with high risk-human papilloma virus infection (HR-HPV) (Pinto et al. 445). Neuroendocrine carcinoma of the cervix is a rare but aggressive cancer and requires a different treatment regime, which necessitates biomarker panel for quick diagnosis (Deavers et al. 572). Popular biomarkers used for diagnosis of CIN1/LSIL is Ki-67 (MIB-1) and p16 (Deavers et al. 570). However, MIB-1 is found to be more useful in differentiating CIN2 and CIN3 (Mittal et al. 415).
Differential diagnosis of HSIL and squamous mimics. HSIL/CIN2 and 3 are positive for Ki-67, ProEx, MIB-1 and p16INK4A but negative for Bcl-2, differentiating it from benign squamous lesions, endometriosis and tuboendometrial metaplasia (Cameron et al. 313; Pinto et al. 1067, Herfs et al. 10516; Pinto et al. 445; Negri et al. 1). However, literature suggests that presence of absence of these biomarkers must be interpreted along with histological evidence (using H&E staining) such as strong diffuse staining of p16INK4A to confirm HSIL (Pinto et al. 445).
Differential diagnosis of HSIL and glandular lesions. Benign glandular lesions are negative for or only weakly positive for p16, negative for p53, carcinoembryonic antigen (CEA) and Ki-67 as opposed to the strong positive staining as shown by CINs (Deavers et al. 571). Histopathological observations such as presence of goblet cells along with intestinal type epithelium, positively indicates endocervical glandular lesion. Hispathology plays an important role in differential diagnosis (McCluggage 140).
Differential diagnosis between endocervical and endometrial adenocarcinoma. Endometrial adenocarcinoma is vimentein+, CEA- while endocervical adenocarcinoma is CEA+, Ki-67+, p53+, vimentin- and ER-.
Summary. As per literature, biomarker panel comprising of Ki-67+, p16+, ProEx+, MIB-1+ could help in CIN/SIL identification while endocervical adenocarcinoma could be identified through CEA+, Ki-67+, p53+, vimentin- and ER-. Similarly, endocervical glandular lesions are CEA-, Ki-67- and p53- with classic histological changes.
Immunohistochemical markers in vulval malignancies
Vulval malignancies can be divided into three categories, namely, vulvar Paget’s disease, vulvar intraepithelial neoplasia (VIN) and vulvovaginal mesenchymal lesions. Cells in Paget’s disease are CK7+, CEA+, CAM 5.2+ and gross cystic disease fluid protein (GCDFP)+ (Goldblum and Hart 1178). VIN histologically appear benign and may progress to squamous cell carcinoma of the vulva if they tested positive for p53 and Ki-67 (Yang and Hart 429; Deavers et al. 576). VIN owing to HPV infections are positive for MIB-1 and p16 while VIN not associated with HPV infections are p16-. Pagetoid VIN is CK7-, S-100- and HMB- (Mittal et al. 414). The level of expression of cyclooxygenase 2 (COX-2) has been associated with poor prognosis of vulvar carcinoma (Fons et al. 756). Vulvovaginal mesenchymal lesions are ER+, PR+ and vementin+ (Mittal et al. 413).
Differential diagnosis of vulvar carcinoma from melanoma and mimics. Paget’s disease can be differentiated from vulvar melanoma as it is negative for S-100 and HMB-45. Diseases such as Bowen disease and fungal lesions mimic Paget’s disease cells are CK7+, CEA+, CAM 5.2+ and GCDFP+ and have positive reaction with HER-2/neu (Goldblum and Hart 1178). Metastasized colorectal cancer to the vulva is characterized by CK20+, CDX-2+ and MUC-2+ whiel metastasized urinary bladder to the vulva is characterized by uroplakin-III+ (Mittal et al. 413).
Summary. Paget’s disease cells are CK7+, CEA+, CAM 5.2+ and GCDFP+ along with reactivity to HER-2/neu. VIN is p53+ and Ki-67+. VIN caused due HPV infection is MIB-1+ and p16+ while VIN not caused by HPV is p16-. Vulvar melanoma are S-100+ and HMB+ while mesenchymal lesions of the vulva are ER+, PR+ and vementin+.
Works Cited
Adekunle, Oguntayo Olanrewaju. "Cervical Intraepithelial Neoplasia (CIN) (Squamous Dysplasia)." Intraepithelial Neoplasia. Ed. Supriya Srivastava. Rijeka, Croatia: InTech, 2012. Print.
Cameron, R. I., et al. "Immunohistochemical staining with MIB1, bcl2 and p16 assists in the distinction of cervical glandular intraepithelial neoplasia from tubo‐endometrial metaplasia, endometriosis and microglandular hyperplasia." Histopathology 41.4 (2002): 313-321.
Chu, Peiguo, and Lawrence M. Weiss. "Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases." Modern Pathology 13.9 (2000): 962-972.
Deavers, M. T., A. Malpica, and E. G. Silva. "Immunohistochemistry in gynecological pathology." International Journal of Gynecological Cancer 13.5 (2003): 567-579.
Fons, Guus, et al. "Assessment of promising protein markers for vulva cancer." International Journal of Gynecological Cancer 19.4 (2009): 756-760.
Goldblum, John R., and William R. Hart. "Vulvar Paget's disease: a clinicopathologic and immunohistochemical study of 19 cases." The American journal of surgical pathology 21.10 (1997): 1178-1187.
Heatley, M. K. "Immunohistochemical biomarkers of value in distinguishing primary ovarian carcinoma from gastric carcinoma: a systematic review with statistical meta‐analysis." Histopathology 52.3 (2008): 267-276.
Herfs, Michael, et al. "A discrete population of squamocolumnar junction cells implicated in the pathogenesis of cervical cancer." Proceedings of the National Academy of Sciences 109.26 (2012): 10516-10521.
Kaspar, Hanna G., and Christopher P. Crum. "The utility of immunohistochemistry in the differential diagnosis of gynecologic disorders." Archives of pathology & laboratory medicine 139.1 (2015): 39-54.
Köbel, Martin, et al. "A limited panel of immunomarkers can reliably distinguish between clear cell and high-grade serous carcinoma of the ovary." The American journal of surgical pathology 33.1 (2009): 14-21.
McCluggage, W. Glenn. "New developments in endocervical glandular lesions." Histopathology 62.1 (2013): 138-160.
Mittal, Khush, and Robert Soslow. "Application of immunohistochemistry to gynecologic pathology." Archives of pathology & laboratory medicine 132.3 (2008): 402-423.
Negri, Giovanni, et al. "Usefulness of p16ink4a, ProEX C, and Ki-67 for the Diagnosis of Glandular Dysplasia and Adenocarcinoma of the Cervix Uteri." International Journal of Gynecologic Pathology 30.4 (2011): 407-413.
Pinto, Alvaro P., Christopher P. Crum, and Michelle S. Hirsch. "Molecular markers of early cervical neoplasia." Diagnostic Histopathology 16.10 (2010): 445-454.
Pinto, Alvaro P., et al. "Biomarker (ProExTM C, p16INK4A, and MiB-1) distinction of high-grade squamous intraepithelial lesion from its mimics." Modern Pathology 21.9 (2008): 1067-1074.
Prat, J. "New insights into ovarian cancer pathology." Annals of Oncology 23.suppl 10 (2012): x111-x117.
Rabban, Joseph T., and Charles J. Zaloudek. "A practical approach to immunohistochemical diagnosis of ovarian germ cell tumours and sex cord–stromal tumours." Histopathology 62.1 (2013): 71-88.
Tanyi, Janos L., and Nathalie Scholler. "Oncology biomarkers for gynecologic malignancies." Front Biosci (Elite Ed) 4 (2012): 1097-1110.
Waldstrøm, Marianne, and Anni Grove. "Immunohistochemical expression of Wilms tumor gene protein in different histologic subtypes of ovarian carcinomas." Archives of pathology & laboratory medicine 129.1 (2005): 85.
Wentzensen, Nicolas, and Magnus von Knebel Doeberitz. "Biomarkers in cervical cancer screening." Disease markers 23.4 (2007): 315-330.
Yang, Bin, and William R. Hart. "Vulvar intraepithelial neoplasia of the simplex (differentiated) type: a clinicopathologic study including analysis of HPV and p53 expression." The American journal of surgical pathology 24.3 (2000): 429-441.
