S-100 protein in ovarian tumors. A comparative immunohistochemical study of 135 cases

The distribution of S-100 protein in 135 ovarian tumors, of which 127 were epithelial, was investigated using the immunoperoxidase method. S-100 protein has been demonstrated previously in tumors of various origins. The present study further revealed its characteristic distribution in common epithelial tumors of the ovary. S-100 protein was present in 69% of serous tumors (benign, 50%; borderline, 100%; malignant, 71%), as well as in the serous elements of serous & mucinous mixed tumors (30%). S-100 protein was also demonstrated in 25% of clear cell carcinomas and 29% of endometrioid carcinomas. Interestingly, none of the mucinous tumors were positive for S-100 protein. In addition, the expression of S-100 protein by epithelial ovarian tumors was compared with that of CA 125 and carcinoembryonic antigen (CEA). The distribution of S-100 protein was similar to that of CA 125, since both antigens were frequently present in serous tumors, although their expression patterns were different. On the other hand, S-100 protein-positive cases were almost negative for CEA or vice versa. Our observations indicate that demonstration of S-100 protein in common epithelial tumors of the ovary and comparison of S-100 protein distribution with that of CA 125 and CEA may further clarify the characteristics of common epithelial tumors of the ovary.     

卵巢上皮性肿瘤肠粘液抗原和癌胚抗原的免疫组织化学研究

应用两种肠粘液抗原（ＬａｒｇｅＩｎｔｅｓｔｉｎａｌＭｕｃｉｎｏｕｓＡｎｔｉｇｅｎ，ＬＩＭＡ，ＳｍａｌｌＩｎｔｅｓｄｔｉｎａｌＡｎｔｉ－ｇｅｎ，ＳＩＭＡ）和ＣＥＡ对７８例卵巢上皮性肿瘤石蜡标本进行免疫组化染色。三种抗原在良性和交界性肿瘤中以腔缘型分布为主，可见恶性肿瘤腔缘、胞浆弥漫分布并随组织学分级的增高趋向于胞浆分布；三种抗原的阳性率在浆液性癌和粘液性癌中的差别不显著，但ＣＥＡ在浆液性癌中表达强度低于粘液性癌（Ｐ＜０．０５）；在子宫内膜样癌中三抗原之阳性率和表达强度均较低，故可以辅助鉴别浆液性癌、粘液性癌和官内膜样癌。ＣＥＡ和ＬＩＭＡ大量出现于癌细胞内的肿瘤更具侵袭性，易致肿瘤扩散转移，预后较差。     

S-100 Protein in Ovarian Tumors

The distribution of S 100 protein in 135 ovarian tumors, of which 127 were epithelial, was investigated using the im-munoperoxidase method. S 100 protein has been demonstrated previously in tumors of various origins. The present study further revealed its characteristic distribution in common epithelial tumors of the ovary. S 100 protein was present in 69% of serous tumors (benign, 50%; borderline, 100%; malignant, 71%), as well as in the serous elements of serous & mucinous mixed tumors (30%). S 100 protein was also demonstrated in 25% of clear cell carcinomas and 29% of endometrioid carcinomas. Interestingly, none of the mucinous tumors were positive for S 100 protein. In addition, the expression of S-100 protein by epithelial ovarian tumors was compared with that of CA 125 and carcinoembryonic antigen (CEA). The distribution of S 100 protein was similar to that of CA 125, since both antigens were frequently present in serous tumors, although their expression patterns were different. On the other hand, S 100 protein positive cases were almost negative for CEA or vice versa. Our observations indicate that demonstration of S 100 protein in common epithelial tumors of the ovary and comparison of S-100 protein distribution with that of CA 125 and CEA may further clarify the characteristics of common epithelial tumors of the ovary.     

Immunohistochemical localization of survivin in serous tumors of the ovary.

The aim of this study was to determine the immunohistochemical distribution of survivin in benign, borderline, and malignant serous tumors of the ovary. Survivin was localized by an indirect immunoperoxidase method in 42 cases of serous tumors of the ovary (15 cystadenomas, 15 borderline tumors, and 12 cystadenocarcinomas). Nuclear staining and cytoplasmic staining were separately scored. Cytoplasmic staining was detected in 27% of adenomas/borderline tumors and in 58% of carcinomas. Nuclear staining was detected in 87% of adenomas/borderline tumors but in only 42% of carcinomas. Although the differences in the intensity of cytoplasmic staining between adenomas and borderline tumors versus carcinomas were not significant, the differences in the intensity of nuclear staining between low-grade versus malignant tumors were significant. These findings suggest that survivin is widely expressed in benign, borderline, and malignant serous tumors but that nuclear localization of survivin is more common in benign or borderline tumors than in malignant serous tumors of the ovary. The molecular mechanisms that determine the subcellular distribution of this protein may reflect the role of survivin in the regulation of apoptosis during the processes of malignant transformation.     

Loss of cables, a novel gene on chromosome 18q, in ovarian cancer.

Cables, a cyclin-dependent kinase (cdk) interacting protein, has recently been identified and mapped to human chromosome 18q11. Cables appears to be primarily involved in cell cycle regulation and cell proliferation. Overexpression of Cables in Hela and other cell lines inhibits cell proliferation and tumor formation. We hypothesize that loss of Cables expression is associated with ovarian cancer. To test our hypothesis, we examined Cables expression in the four most common subtypes of ovarian carcinomas: serous, endometrioid, mucinous, and clear cell. In addition, mucinous and serous borderline tumors were also included. Loss of Cables expression was observed at high frequency in ovarian serous (11 of 14 cases, 79%) and endometrioid (5 of 10 cases, 50%) carcinomas. In contrast, strong Cables staining was detected in all clear cell carcinomas (10 cases) and mucinous tumors (5 carcinomas and 5 borderline tumors). The majority of serous borderline tumors (11 of 14 cases, 79%) showed positive Cables staining, with the rest showing focal loss of Cables expression. Furthermore, RT-PCR revealed the lack of Cables mRNA in a human ovarian cancer xenograft. No correlation was noted between loss of Cables and histologic grade, tumor stage, and survival. In conclusion, our results indicate that loss of Cables is common in ovarian serous and endometrioid carcinomas and imply that Cables may be involved in the pathogenesis of these two types of ovarian carcinomas.     

Nuclear findings of ovarian surface epithelial tumors

While cytoplasmic features of ovarian surface epithelial tumors are well-known, the nuclear findings have received little attention. We reviewed imprint cytology materials of the ovary which were collected at the Kawasaki Medical School Hospital between January 1989-July 1999, and identified 15 mucinous cystadenomas, 3 borderline mucinous tumors, 4 mucinous cystadenocarcinomas, 4 serous cystadenomas, 4 borderline serous tumors, 7 serous cystadenocarcinomas, 6 endometrioid carcinomas, and 2 clear-cell adenocarcinomas. We microscopically observed nuclear findings of the 45 cases. Coffee-bean nuclei were observed in 15.0%, 15.8%, and 10.1% of the tumor cells in mucinous adenomas, borderline mucinous tumors, and borderline serous tumors, respectively. The frequencies of the coffee-bean nuclei in the three tumors were higher than in the remaining tumors (P < 0.001). Intranuclear cytoplasmic inclusions were observed in 2.1% of the tumor cells in mucinous cystadenoma, and their frequency was significantly higher than that in cases of other surface epithelial ovarian tumors (P < 0.001). Semilunar-shaped nuclei were seen in all cases of mucinous cystadenomas and borderline mucinous tumors, and in 3 of 4 mucinous adenocarcinomas. The remaining surface epithelial tumors did not reveal the semilunar-shaped nuclei. In the cytology of the ovary, the semilunar nuclei are characteristic of mucinous tumors, and the intranuclear cytoplasmic inclusion may be a diagnostic clue to mucinous cystadenoma, when it is conspicuous. The coffee-bean nuclei can be seen in mucinous cystadenoma, borderline mucinous tumors, and borderline serous tumors.     

Overexpression of p21WAF1/CIP1 and MDM2 characterizes serous borderline ovarian tumors

Ovarian epithelial tumors are classically divided into benign, malignant, and borderline or of low malignant potential. It is controversial whether this last group of tumors should be considered benign or malignant. Expression of cell cycle markers has recently been linked to tumor behavior and response to treatment. It has been shown that one of the pathways through which the p53 gene controls the cell cycle is by transactivating p21WAF1/CIP1, a cyclin-dependent kinase (cdk) inhibitor. By inhibiting cdks, p21WAF1/CIP1 blocks the G-1 to S-phase transition in the cell cycle. p53 can be regulated by MDM2 (murine double minute-2) through direct inactivation or promotion of its cytoplasmic degradation. In an attempt to investigate the cell cycle checkpoint mechanisms of these tumors, we studied the expression of p53, Ki-67, MDM2, and p21WAF1/CIP1 by immunohistochemistry. We analyzed the expression of these proteins in 19 cystadenomas (8 serous and 11 mucinous), 40 borderline tumors (31 serous and 9 mucinous), and 18 serous carcinomas of the ovary. p21WAF1/CIP1 was expressed in 7 of 19 (37%) benign cystadenomas, 32 of 40 (80%) borderline tumors (93.5% of serous and 33% of mucinous), and in 9 of 18 (50%) serous carcinomas. Ki-67 was only weakly expressed in 8 of 19 (42%) benign cystadenomas, all borderline tumors showed Ki-67 staining in less than 50% of the cells, and 55% of serous carcinomas stained in more than 50% of tumor cells. p53 was absent in all but 1 of the cystadenomas, was expressed in 9 of 40 (22.5%) borderline tumors (25.8% of serous and 11% of mucinous), and in 10 of 18 (55%) carcinomas. All 11 implants of serous borderline tumors expressed p21WAF1/CIP1. Most serous borderline tumors expressed higher levels of MDM2 compared with the benign cystadenomas and carcinomas. Four of the serous borderline implants (40%) expressed MDM2. Coexpression of p21WAF1/CIP1 and MDM2 characterizes serous borderline tumors of the ovary and their implants, which suggests that these cell cycle control proteins are important in these tumors and may be related to tumor progression. Low expression of p53 protein in serous borderline tumors might be in part mediated by MDM2. This suggests that the p53 pathway is intact in most of these tumors, in contrast with carcinomas, in which high expression of p53 has been related to mutations of this gene.     

Comparison of glycoprotein expression between ovarian and colon adenocarcinomas.

OBJECTIVE: Tumor-associated antigens may be expressed as surface glycoproteins. These molecules undergo qualitative and quantitative modifications during cell differentiation and malignant transformation. During malignant transformation, incomplete glycosylation is common, and certain glycosylation pathways are preferred. These antigens might help distinguish between ovarian and colonic adenocarcinomas in the primary and metastatic lesions. Different cytokeratins have been proposed as relatively organ-specific antigens. DESIGN: We used monoclonal antibodies against T1, Tn, sialosyl-Tn, B72.3, CA125, carcinoembryonic antigen, and cytokeratins 7 and 20 to detect tumor-associated glycoproteins and keratin proteins in ovarian and colonic carcinomas. RESULTS: CA125, carcinoembryonic antigen, and cytokeratins 7 and 20 can distinguish between colonic and serous or endometrioid adenocarcinomas of the ovary in both primary and metastatic lesions. Mucinous ovarian adenocarcinomas differed in that they express carcinoembryonic antigen and cytokeratins 7 and 20 and weakly express CA125. The other glycoprotein antigens were equally expressed by ovarian and colonic adenocarcinomas and therefore were of no use in distinguishing between these 2 entities. CONCLUSION: A panel of monoclonal antibodies against cytokeratins 7 and 20 antigens, CA125, and carcinoembryonic antigen is useful in differentiating serous and endometrioid adenocarcinomas of the ovary from colonic adenocarcinomas. Mucinous ovarian adenocarcinomas cannot be distinguished from colonic adenocarcinomas using immunohistochemistry.     

Uncommon ovarian epithelial tumours

Epithelial ovarian tumours represent the most common type of ovarian tumour. Most of malignant cases represent high-grade serous, clear cell and endometrioid carcinomas; borderline serous and mucinous tumours of intestinal type are less common. This review focuses on the uncommon or rare epithelial tumours of the ovary which include borderline and malignant Brenner tumours, the recently-described mesonephric-like carcinoma of the ovary, and primary ovarian neuroendocrine tumours, with emphasis on helpful and diagnostic features.     

Increasing expression of serine protease matriptase in ovarian tumors: tissue microarray analysis of immunostaining score with clinicopathological parameters.

Matriptase is a type II transmembrane serine protease expressed by cells of surface epithelial origin, including epithelial ovarian tumor cells. Matriptase cleaves and activates proteins implicated in the progression of cancer and represents a potential prognostic and therapeutic target. The aim of this study was to examine the expression of matriptase in ovarian tumors and to assign clinicopathological correlations. Immunohistochemical analysis of matriptase was performed in tissue microarrays of 164 ovarian neoplasms including 84 serous adenocarcinomas, 23 mucinous adenocarcinomas, 10 endometrioid adenocarcinomas, six yolk sac tumors, 12 clear cell carcinomas, six dysgerminomas, eight granulosa cell tumors, four transitional cell carcinomas, five fibromas, and six Brenner tumors. All ovarian tumors except the fibromas and Brenner tumors showed significant expression of matriptase. The matriptase scores were significantly higher in the tumors than in their nontumor counterparts (304+/-26 for serous adenocarcinoma; 361+/-28 for mucinous adenocarcinoma; 254+/-17 for endometrioid adenocarcinoma; 205+/-19 for yolk sac tumor; 162+/-16 for clear cell carcinoma; 109+/-11 for dysgerminoma; 105+/-9 for granulosa cell tumor; and 226+/-18 for transitional cell carcinoma). Matriptase scores in serous adenocarcinoma were correlated with TNM stage and FIGO stage. Our findings demonstrate for the first time that matriptase is overexpressed in many malignant ovarian tumors. It may be a novel biomarker for diagnosis and treatment of malignant ovarian tumors.     

Insulin-like growth factor-binding protein 2 and 5 are differentially regulated in ovarian cancer of different histologic types.

The family of insulin-like growth factor-binding proteins (IGFBPs) comprises six members, which bind and regulate the functions of insulin-like growth factors. Overexpression of IGFBP2 and IGFBP5 contributes to the invasiveness and progression of several human cancers, but their role and clinical significance in ovarian cancer has not been investigated in detail. We examined IGFBP2 and IGFBP5 expression levels using two tissue microarrays, one containing six normal surface epithelium, six benign serous cysts, 10 serous borderline tumors, eight low-grade, and 20 high-grade serous carcinomas. The other comprising 441 ovarian cancers of different histologic types linked to a clinicopathologic database. Each tumor was sampled in duplicate with a 1.0-mm punch core needle. Immunohistochemical staining was performed using antibodies against IGFBP2 or IGFBP5. The staining intensity was scored semiquantitatively as negative (0), weak (1-10%), moderate (10-50%), or strong (50-100%) using computerized image analysis. Statistical analyses used Fisher's exact test and Kaplan-Meier method. IGFBP2 and IGFBP5 were overexpressed in high-grade serous carcinomas compared to normal surface epithelium, benign serous cysts, serous borderline tumors, or low-grade serous carcinoma. They were differentially expressed in different types of ovarian carcinomas, being more often expressed at high levels in high-grade serous carcinoma, malignant mixed mullerian tumors and undifferentiated carcinoma, and more often expressed at low levels or not at all in clear cell and mucinous carcinomas. We concluded that IGFBP2 and IGFBP5 might play a role in the development of high-grade ovarian serous carcinoma, but not in mucinous or clear cell ovarian carcinomas.     

Hyaline globules in ovarian tumours

Hyaline eosinophilic globules have so far been described in a restricted variety of tumour types. We have noted their presence in a variety of gynaecological malignancies, in particular mixed Müllerian tumours and other epithelial ovarian tumours. We therefore studied their incidence and distribution in a series of malignant, borderline and benign epithelial ovarian tumours, and endometrial and endocervical adenocarcinomas. Hyaline eosinophilic globules were found in all 30 mixed Müllerian tumours from various sites in the female genital tract, 22 of 30 clear cell carcinomas, seven of 30 serous, two of 30 mucinous, and one of 30 endometrioid carcinomas examined, and were also seen in metastases from these tumours. They were present in only two of 25 borderline serous, one of 25 borderline mucinous tumours, and in four of 50 benign serous and one of 50 benign mucinous tumours. The globules were not found in any of 25 Brenner tumours examined, nor in 30 endometrial or 30 endocervical adenocarcinomas. The globules were periodic acid–Schiff positive after diastase, stained positively with PTAH, and were immunoreactive for α-1-antitrypsin. This study therefore demonstrates that eosinophilic globules are not specific for any particular tumour. However, their frequency in malignant mixed Müllerian tumours suggests that this diagnosis should be carefully excluded whenever these globules are present in epithelial tumours of the female genital tract.     

Histological classification of ovarian cancer

The histology of ovarian tumors exhibits a wide variety of histological features. The histological classification of ovarian tumors by the World Health Organization (WHO) is based on histogenetic principles, and this classification categorizes ovarian tumors with regard to their derivation from coelomic surface epithelial cells, germ cells, and mesenchyme (the stroma and the sex cord). Epithelial ovarian tumors, which are the majority of malignant ovarian tumors, are further grouped into histological types as follows: serous, mucinous, endometrioid, clear cell, transitional cell tumors (Brenner tumors), carcinosarcoma, mixed epithelial tumor, undifferentiated carcinoma, and others. Clear cell and endometrioid carcinomas are highly associated with endometriosis. In stage distribution, serous carcinoma is found predominantly is stage III or IV. In contrast, clear cell and endometrioid carcinomas tend to remain confined to the ovary. Clear cell and endometrioid carcinomas may be unique histological types compared with serous carcinomas with respect to stage distribution and association with endometriosis.     

Molekularpathologie der epithelialen Ovarialneoplasien

Despite the fact that ovarian carcinomas are phenotypically heterogeneous, they can be divided into two main groups with common pathogenetic mechanisms. Based on clinical, pathological and molecular parameters, a relatively large group of tumors can be distinguished with stepwise development from benign precursors and borderline tumors to invasive carcinomas (type I). Depending on the morphological phenotype, characteristic genetic changes can be observed, such as mutations in KRAS and BRAF in serous borderline tumors and low-grade serous carcinomas. Mutations in KRAS are also frequently detected in mucinous borderline tumors and mucinous carcinomas. The group of endometrioid tumors is characterized by mutations in components of the Wnt-signal transduction pathway and PTEN or microsatellite instability. The second large group of tumors (type II) includes tumors with "de novo" development of highly malignant carcinomas such as the conventional (moderately to poorly differentiated) high-grade serous carcinomas, undifferentiated carcinomas and malignant mixed mesodermal tumors. These tumors are associated with frequent mutations in p53 and complex chromosomal alterations. In the future, the combined analysis of morphological parameters, genetic changes, gene-expression profiling and protein data will reveal possible diagnostic and therapeutic targets for ovarian carcinomas.     

β-Catenin Expression Pattern in Stage I and II Ovarian Carcinomas : Relationship with β-Catenin Gene Mutations, Clinicopathological Features, and Clinical Outcome

The immunohistochemical expression pattern of beta-catenin has been correlated with beta-catenin gene mutations, clinicopathological features, and disease outcome in 69 stage I and II ovarian carcinomas. beta-Catenin expression was localized in the nuclei, in addition to the cytoplasm and membrane, in 11 tumors (16%): nine endometrioid carcinomas with widespread nuclear expression and two serous carcinomas with focal nuclear expression. The remaining 58 carcinomas (84%) only had membranous beta-catenin expression. All but one of the endometrioid carcinomas with nuclear beta-catenin expression had considerable squamous metaplasia, and five of these cases had large areas of endometrioid tumor of low malignant potential. In addition, beta-catenin nuclear expression was observed in atypical epithelial cells in endometriotic glands adjacent to an endometrioid carcinoma. Sequencing was performed on 25 tumors and corresponding normal tissue: all 13 endometrioid tumors as well as 12 carcinomas of other histological types (four serous, two clear cell, two mucinous, and two mixed). There were oncogenic mutations in the phosphorylation sequence for GSK-3beta in exon 3 of the beta-catenin gene in seven endometrioid carcinomas with beta-catenin nuclear expression. Three mutations affected codon 32 (D32G, D32Y, and D32Y), one affected codon 33 (S33C), two affected codon 37 (S37C and S37F), and one affected codon 41 (T41A). No mutations were observed in the other 18 carcinomas analyzed, comprising two endometrioid and two serous carcinomas with beta-catenin nuclear expression, and 14 carcinomas of different histological types with only membranous expression. In the univariate and multivariate survival analyses, beta-catenin nuclear expression was selected as an indicator of good prognosis, because no patient whose tumor expressed beta-catenin in the nuclei showed relapses or died, in contrast to the 19 relapses and deaths among patients with tumors that only had beta-catenin membranous expression, including three of the four patients with endometrioid carcinomas. Oncogenic beta-catenin mutation is characteristic of a group of endometrioid carcinomas with a good prognosis, most of which originate from previous benign or borderline lesions. Endometrioid carcinomas with exclusively membranous expression of beta-catenin seem to represent a different subgroup of carcinomas that probably have a worse prognosis. In early-stage ovarian cancer, determination of the beta-catenin expression pattern could prove to be a useful marker for selecting low-risk patients.     

Evolution of the concept and termiology of borderline ovarian tumours

The borderline category of ovarian tumours was established in the early 1970s because of the observation that a group of proliferative epithelial ovarian tumours lacking invasion that generally behaved in a benign fashion occasionally pursued an indolent malignant course. Over the last 25 years, a large database on these tumours has been accrued. Recent studies suggest that the borderline group can now be subclassified into benign and malignant neoplasms. The survival for patients with serous borderline tumours confined to the ovaries is virtually 100%. Patients with ovarian serous borderline tumours with invasive peritoneal implants have a 34% mortality rate; therefore, these cases are classified as low grade carcinomas. Micropapillary serous carcinoma, a distinctive neoplasm that fails to display unequivocal evidence of invasion and therefore has been included in the borderline category, is strongly associated with invasive implants and recurs as invasive carcinoma. After these neoplasms with invasive implants are excluded from the group of tumours classified as borderline, the remaining advanced stage serous borderline tumours (those with non-invasive implants) have a disease-specific survival rate of nearly 100% and should be considered benign. In a similar fashion, the vast majority of mucinous borderline tumours reported to display aggressive behaviour have been associated with the clinical syndrome of pseudomyxoma peritonei. It is now clear that pseudomyxoma peritonei is a condition of appendiceal origin in virtually all cases. In addition, there is a small group of mucinous carcinomas typically from the pancreas and biliary system that present with relatively bland-appearing metastases to the ovaries that closely simulate mucinous borderline tumours. Once these metastatic carcinomas and mucinous tumours associated with pseudomyxoma peritonei are removed from the borderline category, the remaining mucinous borderline tumours are always confined to the ovaries and have a benign behaviour. Finally, review of the literature indicates the other epithelial types of borderline tumours (endometrioid, clear cell and transitional cell) behave in a benign fashion. Since borderline tumours can now be classified into benign and malignant types, the borderline category has no further utility and can be abandoned. This will be of great benefit to patients and clinicians, and will also help in more clearly focusing research efforts on ovarian cancer.     

Expression of hepatocyte nuclear factor-1beta (HNF-1beta) in clear cell tumors and endometriosis of the ovary.

Clear cell tumors of the ovary are frequently associated with ovarian endometriosis. Clinicopathologically, it has been suggested that clear cell tumors develop from endometriosis, but there has been little molecular evidence supporting this speculation. Microarray analysis revealed recently that hepatocyte nuclear factor-1beta (HNF-1beta) was significantly upregulated in clear cell carcinoma of the ovary. In the present study, we examined 30 clear cell tumors (26 malignant, three borderline, and one benign) and 40 endometriotic cysts to clarify if differentiation into the clear cell lineage already begins in ovarian endometriosis. All of the 30 clear cell tumors, including borderline and benign ones, showed immunohistochemical expression of HNF-1beta in the nucleus, while other types of ovarian epithelial tumors (endometrioid, serous, mucinous, and Brenner tumors) rarely expressed it. Among 30 clear cell tumors, 17 (56%) cases were associated with endometriosis, and endometriotic epithelium was identified in 12 cases. In nine of the 12 cases, distinct nuclear immunostaining for HNF-1beta was detected in the endometriotic epithelium, as well as in the clear cell tumor. HNF-1beta expression was observed either in atypical endometriosis (four cases), or in endometriosis of a reactive nature (five cases). Furthermore, 16 of 40 (40%) endometriotic cysts without a neoplasm also expressed HNF-1beta, and the expression was almost exclusively observed in the epithelium showing inflammatory atypia. Our results indicate that HNF-1beta is an excellent molecular marker for ovarian clear cell tumors, including benign, borderline and malignant lesions. Early differentiation into the clear cell lineage takes place in ovarian endometriosis, not only in atypical endometriosis, but also in endometriosis with degenerative and regenerative changes, and this is probably responsible for the frequent occurrence of clear cell carcinoma in ovarian endometriosis.     

Immunohistochemical localization of CA 125 antigen in formalin-fixed paraffin sections of ovarian tumors with the use of Pronase

The OC 125 monoclonal antibody was used to localize CA 125 antigen in routine paraffin sections of ovarian tumors with the use of a modified avidin-biotin-peroxidase complex (ABC) technic. Pretreatment of the paraffin sections with Pronase allowed subsequent detection of CA 125 antigen. OC 125 stained 4 (80%) of 5 benign and borderline serous ovarian tumors, 12 (86%) of 14 serous adenocarcinomas, and 3 (23%) of 13 benign and malignant mucinous ovarian tumors. The pattern of distribution of CA 125 antigen was mostly at the intraluminal and peripheral cell surfaces, while intracytoplasmic staining also was seen. Overall, CA 125 antigen detectability rate in paraffin sections was found to be compatible with those reported in frozen sections. The method allows retrospective immunohistochemical examination of a large number of cases with ovarian tumors.