SOX17 expression in mesonephric-like adenocarcinomas and mesonephric remnants/hyperplasia of the female genital tract: Expanding its utility as a Müllerian biomarker.

AIMS: Recently, SOX17 has emerged as a promising biomarker for non-mucinous Müllerian (ovarian and endometrial) carcinomas, demonstrating increased specificity in comparison to PAX8 while maintaining similar sensitivity. However, expression of SOX17 in mesonephric-like adenocarcinoma (MLA), a carcinoma of the female genital tract with uncertain, but probably Müllerian histogenesis, remains unexplored. This study aims to address this gap. METHODS AND RESULTS: SOX17 immunohistochemistry was performed on whole tissue sections from 68 MLAs originating from the endometrium or ovary and seven cervical mesonephric carcinomas, as well as six mesonephric remnants/hyperplasias. Using a four-tiered scoring system based on distribution and intensity of staining, 68% of MLA displayed a negative/low (< 10%) SOX17 expression pattern, which contrasts with the high expression observed in most Müllerian carcinomas. However, 22% of MLA demonstrated high SOX17 expression, similar to other endometrial and ovarian carcinomas. Similarly, five of seven (72%) mesonephric carcinomas of the cervix were SOX17-negative, but two cases (28%) were positive. All mesonephric remnants/hyperplasias were SOX17 negative. CONCLUSIONS: The majority of MLA are negative or exhibit low SOX17 expression, in contrast to the diffuse and strong expression commonly seen in other types of Müllerian carcinoma. However, a subset of MLAs demonstrate high SOX17 expression. Therefore, absence of SOX17 staining is supportive for MLA when the differential includes another non-mucinous Müllerian carcinoma. SOX17 may also be useful for differentiating mesonephric remnants/hyperplasias from Müllerian malignancies and benign Müllerian glandular lesions.

Deposition of fibronectin and laminin in the basement membrane of the rat parietal yolk sac: immunohistochemical and biosynthetic studies.

Rat parietal yolk sacs (PYS) at gestational ages 7.5, 9.5, 11.5, 13.5, 14.5, and 16.5 d were reacted with antibodies against laminin or plasma fibronectin. At all times studied, laminin consistently gave a positive reaction with Reichert's membrane and with the cytoplasm of PYS cells. In contrast, fibronectin gave a negative reaction with Reichert's membrane at day 7.5, was weakly positive at day 9.5, and from then on was increasingly positive with maximum reactivity at 14.5 d. By electron microscopic immunohistochemistry, antilaminin reacted strongly with 14.5-d Reichert's membrane and with the contents of the rough endoplasmic reticulum RER cisternae of the PYS cells. Antifibronectin had some spotty reactivity with Reichert's membrane, but the cytoplasm of the PYS cells was negative. The contents of the vitelline vessels and the interface between trophoblast and Reichert's membrane were strongly positive. Metabolic labeling of PYS cells in organ culture clearly demonstrated the presence of laminin, type IV procollagen, and entactin both in the medium and in tissues, but fibronectin was absent. No component in the medium bound to gelatin-Sepharose columns. These studies demonstrate that PYS cells, which actively synthesize and secrete basement membrane components, do not synthesize any detectable fibronectin. Furthermore, the anti-fibronectin staining pattern in the vitelline vessels and trophoblast-Reichert's membrane interface strongly suggests that the fibronectin present in Reichert's membrane is derived from the maternal circulation and is merely "trapped" in the membrane.

Characterization of the fibronectin synthesized by human germ cell tumors.

The ability of the human germ cell tumor cell lines Tera 1, Tera 2, PA-1, LICR LON HT 39/7, LICR LON HT3B1, and LICR LON HT 53 to synthesize and secrete fibronectin has been studied. The presence of cellular fibronectin was examined using indirect immunofluorescence, whereas the synthesis and secretion of the protein were studied using specific immunoprecipitation from cultures radioactively labeled with [35S]methionine. Two of the cell lines, LICR LON HT 39/7 and Tera 1, did not synthesize fibronectin, whereas all the other cell lines did. Plasma membrane fibronectin could not be demonstrated on any of the cell lines, although cytoplasmic fibronectin was easily demonstrable. The cells appear therefore to synthesize fibronectin but not retain it. Sodium dodecyl sulfate:polyacrylamide gel electrophoresis of the secreted fibronectin produced by the human teratoma cell lines showed that it had an apparent molecular weight greater than that produced by adult human breast fibroblasts or human plasma fibronectin. Peptide mapping of this secreted germ cell tumor fibronectin, by partial proteolytic cleavage, yielded peptide patterns similar to those obtained from either human plasma fibronectin or adult human breast fibroblast fibronectin. The difference in molecular weight between the fibronectins may therefore be due to changes in their patterns of glycosylation.

Protein synthesis by rat transplantable yolk sac tumor and its relation to the cytosol levels of translatable messenger RNA's.

alpha-Fetoprotein (AFP) was shown to be the major secretory protein produced in vitro by normal rat yolk sacs. While not so active, AFP production was also detected in the transplantable tumors derived from normal yolk sacs. The major secretory protein synthesized by the tumor cells had a molecular weight of 40,000 and was reactive with an anti-rat albumin antibody. The functional messenger RNA's coding for these proteins were quantitated by translation in a cell-free system derived from wheat germ followed by specific immunoprecipitation of the newly synthesized peptides. The overall template activity of the RNA prepared from the normal yolk sacs and yolk sac tumor cells was virtually identical. The cytosol RNA prepared from the normal yolk sacs was approximately 12 times more active than that from the tumor cells in directing the synthesis of AFP. The presence of the cytosol RNA prepared from the tumor cells was required for the synthesis of proteins immunoprecipitable with the antialbumin antibody. These results suggest that the changes in AFP and albumin synthesis can be accounted for by a corresponding change in the levels of functional messenger RNA's coding for these proteins.

Laminin, a noncollagenous component of epithelial basement membranes synthesized by a rat yolk sac tumor.

Laminin, a glycoprotein antigenically similar or identical to a component of epithelial basement membranes, was identified as a major component of the abundant extracellular matrix synthesized by an experimentally induced rat yolk sac tumor. Immunocytochemical staining revealed laminin in cultured tumor cells as well as in their extracellular matrix. The presence of soluble laminin in the culture media of the tumor cells was demonstrated using metabolic labeling followed by identification by immunoprecipitation and sodium dodecyl sulfate:polyacrylamide gel electrophoresis. This revealed two polypeptides with molecular weights of approximately 200,000 and 400,000. These comigrated with the polypeptides of mouse laminin isolated previously. The yolk sac tumor tissue grown in vivo contained laminin in the tumor cells and in the extracellular material as evidenced by immunofluorescence and immunoperoxidase staining. Immunization with the tumor matrix resulted in an antiserum that contained antilaminin and natifibronectin and was made specific for laminin by absorption with fibronectin. This antiserum precipitated laminin polypeptides from culture medium of yolk sac tumour cells and stained basement membranes in rat tissues in a manner indistinguishable from antilaminin. The presence of laminin in rat yolk sac cells, the presumed origin of our yolk sac tumor, was studied in some detail. Laminin was found to be present in normal cells of the visceral as well as the parietal yolk sac layer and in their basement membranes suggesting, but not proving, that both types of cells have ability to synthesize laminin. Production of laminin and the presence of laminin-containing basement membrane material may be important for the biological behavior of the yolk sac tumor. This tumor will also be a useful source of laminin for chemical and biological characterization of this basement membrane protein.

CD10 expression in epithelial tissues and tumors of the gynecologic tract: a useful marker in the diagnosis of mesonephric, trophoblastic, and clear cell tumors.

We tested 417 cases of formalin-fixed, paraffin-embedded normal or hyperplastic gynecologic tissues as well as neoplasms involving the gynecologic tract with a monoclonal antibody against CD10 (clone 56C6), with special emphasis on epithelial and epithelial-like structures and tumors. CD10 was always expressed in mesonephric remnants (mesonephric remnants of the uterine cervix, epoophoron, rete ovarii) and tumors (mesonephric adenocarcinoma of the uterine cervix, tumors of wolffian origin of the broad ligament and ovary). CD10 was also positive in the syncytiotrophoblast, cytotrophoblast, and intermediate trophoblast of normal gestations, partial and complete moles, choriocarcinoma, and placental site trophoblastic tumors. Finally, CD10 was positive in several metastatic neoplasms to the gynecologic tract (100% in metastatic renal clear cell and intestinal carcinomas and melanomas). In contrast, CD10 was almost invariably negative in müllerian epithelia of the female genital tract and in their corresponding tumors, with the exception of focal expression found in squamous epithelia and tumors with squamous differentiation. Thus, the expression of CD10 may be useful in the establishing the diagnosis of mesonephric and trophoblastic tumors and in the differential diagnosis between gynecologic clear cell carcinoma (always negative) and metastatic clear cell carcinoma of renal origin.

Rete testis hyperplasia with hyaline globule formation. A lesion simulating yolk sac tumor.

The presence of eosinophilic, hyaline globules in association with epithelial hyperplasia was noted in the rete testis of three patients with germ cell tumors. In the more florid examples, this proliferation formed a solid and microcystic pattern that, in association with the hyaline globules, mimicked a yolk sac tumor component. However, the bland cytologic features of the cells and the conformation to the configuration of the rete testis were keys to its reactive nature. A subsequent review of 48 testicular specimens containing well-defined areas of the rete testis showed hyaline globule formation in the rete testis or tubuli recti in 16 of 27 germ cell tumors, one of five other testicular tumors (four stromal tumors and one plasmacytoma), and none of 16 nonneoplastic cases. Many of the cases that had hyaline globules also showed epithelial hyperplasia. Further analysis demonstrated an incidence of rete testis invasion by neoplasm in cases that had hyaline globules, with or without epithelial hyperplasia, that was significantly higher (p less than 0.01) than that seen in neoplastic cases lacking hyaline globules. We concluded that this pseudoneoplastic reaction developed secondary to invasion of the rete testis by tumor. Immunostains supported the nonneoplastic nature of the proliferative lesions and indicated that the globules represented various proteins that had been absorbed from the lumen of the rete testis by the epithelial-lining cells but not successfully secreted.

Mesonephric adenocarcinoma of the uterine corpus: CD10 expression as evidence of mesonephric differentiation.

Mesonephric (wolffian) neoplasms of the female genital tract are infrequent and found in sites where embryonic remnants of wolffian origin are usually detected, such as the uterine cervix, broad ligament, mesosalpinx, and ovary. Their diagnosis is difficult because of the absence of specific immunohistochemical markers for mesonephric derivatives. We present the first report of adenocarcinoma of mesonephric type arising as a purely myometrial mass without endometrial or cervical involvement in the uterine corpus of a 33-year-old woman. The tumor showed a combination of patterns, with retiform areas, ductal foci, and small tubules with eosinophilic secretion, which merged with solid sheets of cells with a sarcomatoid appearance. Immunohistochemically, neoplastic cells were diffusely positive for cytokeratin 7, epithelial membrane antigen, and CD15 and focally positive for BerEP4 and vimentin. A hitherto unreported feature was the positivity for CD10 in neoplastic cells, which was also present in a large number of control tissues obtained from male mesonephric derivatives and female mesonephric remnants and tumors. Furthermore, CD10 was negative in controls from müllerian epithelia of the female genital tract and in their corresponding tumors. Therefore, the expression of CD10 by mesonephric remnants may be useful in establishing the diagnosis of tumors with mesonephric differentiation.

Primary pulmonary alpha-fetoprotein-producing malignant germ cell tumor.

We are reporting the clinical and pathologic features of a primary, pulmonary, malignant germ cell tumor associated with a marked elevation of serum alpha-fetoprotein (38,427 ng/mL) and lactate dehydrogenase activity (756 U/L), in a 26-year-old female. This controversial, rare neoplasm has not been extensively discussed in the pathology literature. We emphasize the clinical importance of establishing this diagnosis in view of the favorable response to chemotherapy shown by malignant germ cell tumors.

Germ cell neoplasms of head and neck soft tissues: a pathologic spectrum of teratomatous and endodermal sinus tumors.

Germ-cell neoplasms, in particular teratomas with immature and mature somatic type tissues, are some of the most commonly found tumors in children. Approximately 5% of these neoplasms appear in one of several extracranial sites in the head and neck region. This study reports the clinical, pathologic and immunohistochemical findings in six germ-cell neoplasms occurring in the neck and facial areas. A mass was recognized at birth in five children, and the sixth patient was 2 1/2 years old at diagnosis. Four of the six neoplasms contained one or another element of endodermal sinus tumor; two of these had a mixed pattern of endodermal sinus tumor and teratoma. The other two cases were purely teratomas. The serum alpha-fetoprotein was known to be elevated in three children whose tumors had endodermal sinus elements; it returned to normal level in two of the children, but remained high in the one fatal case. Placental alkaline phosphatase and alpha-fetoprotein were demonstrated immunohistochemically in two of the three cases, with available tissue containing endodermal sinus tumor. Teratomatous metastases in ipsilateral cervical lymph nodes were found in one patient with a pure teratoma; that patient is disease-free one year after surgery. Only nine previous examples of endodermal sinus tumor have been reported in the head and neck region, exclusive of the central nervous system. There is one other case in the literature of a congenital cervicothyroidal teratoma with metastatic disease. These six neoplasms illustrate the clinical and pathologic spectrum in this nosologically homogeneous, but morphologically diverse, category of tumors.

Laminin in testicular germ cell tumours. An immunohistochemical study.

Thirty-five testicular germ cell tumours comprising 16 yolk sac tumours, 15 embryonal carcinomas and 13 seminomas were examined for the presence and distribution of laminin using an indirect immunoperoxidase technique. In addition, nine normal yolk sacs and 23 carcinomas of the lung were studied. All the yolk sac tumours were positively stained for laminin. Both extra- and intracellular staining were found. Hyaline, eosinophilic material present within the tumours was positively stained, although with varying intensity. In 12 out of 15 embryonal carcinomas, laminin was found as a membrane staining but cytoplasmic staining also occurred. In 10 out of 13 classical seminomas, a membrane staining of many tumour cells was found, while cytoplasmic staining occurred in only a few seminomas. In all but one of the yolk sacs, laminin was present in the membrane beneath both the mesoblastic outer cell layer and the visceral endoderm. Intracellular staining was seen in some of the cells in both cell layers. In nine out of 23 carcinomas of the lung, laminin occurred extra- as well as intracellularly. Thus, this study showed that in normal yolk sacs the presence of laminin was not found to be particularly associated with any of the cell layers. Likewise, demonstration of laminin within yolk sac tumours did not define different patterns or subtypes of the yolk sac tumour. In addition, demonstration of laminin was not found to be useful in differentiating either between yolk sac tumours and embryonal carcinomas or between seminomas and non-seminomatous germ cell tumours. The findings add, however, interesting knowledge to histogenesis and embryogenesis.

Immunohistochemical differentiation of clear-cell carcinoma of the female genital tract and endodermal sinus tumor with the use of alpha-fetoprotein and Leu-M1.

The morphologic differentiation between clear-cell carcinoma and endodermal sinus tumors is difficult at times. To improve the accuracy of the diagnosis, the authors studied nine ovarian and eight vaginal clear-cell carcinomas and seven endodermal sinus tumors of the ovary by immunohistochemical methods with the use of antibodies to alpha-fetoprotein and Leu-M1. Sixteen (94.1%) of the 17 clear-cell carcinomas and two (28.5%) of the seven endodermal sinus tumors reacted for Leu-M1, whereas six (85.7%) of the seven endodermal sinus tumors and three (17.6%) of the 17 clear-cell carcinomas stained for alpha-fetoprotein. Three clear-cell carcinomas and two endodermal sinus tumors showed immunoreactivity for both markers. No reactivity for either of these markers was present in one endodermal sinus tumor and one clear-cell carcinoma. All 13 tumors that stained only for Leu-M1 proved to be clear-cell carcinomas, and the four that reacted exclusively for alpha-fetoprotein were endodermal sinus tumors. Therefore, the authors concluded that positive immunostaining for Leu-M1 and negative immunostaining for alpha-fetoprotein support the differential diagnosis of clear-cell carcinoma, whereas a positive reaction for alpha-fetoprotein and a negative reaction for Leu-M1 favor a diagnosis of endodermal sinus tumor. However, positive or negative staining for both markers appears to have no diagnostic value.

Expression of intermediate filaments and other special markers by testicular germ cell tumors. With reference to embryogenesis.

Distribution of intermediate filament proteins (IFs) and several special markers was studied in 39 testicular germ cell tumors and 8 embryos and foetuses. The similarity and difference between development of germ cell tumor and embryogenesis were immunohistochemically investigated. Seminoma and embryonal carcinoma, as tumoral counterparts of undifferentiated germ cells, were characterized by little IF expression. This study revealed that the maturing and differentiating process in germ cell tumor is different from normal embryonal development and the tumor cells showed leaping maturing steps in tumorigenesis. Immunostaining for IFs helped to discover the further differentiation occurring in embryonal carcinoma and to demonstrate heterogeneous elements in non-seminoma germ cell tumors, which sometimes might not be apparent by light microscopical observation of H&E staining section. According to the findings, two patterns in mixed germ cell tumors are suggested; i.e., combined and diffuse types. The mechanism of tumorigenesis of the two types is supposed to be different. Clinically, the prognosis of most patients with testicular germ cell tumor is fairly good because of the improved chemotherapies that are dependent on histological diagnosis.

Human endodermal sinus tumour in nude mice and its markers for diagnosis and management.

Two human endodermal sinus tumours (yolk sac tumours) were transplanted successfully into nude mice. The transplanted tumours maintained not only morphological characters, such as Schiller-Duval bodies, but also the ability to synthesise alpha-fetoprotein, lactic dehydrogenase 1, liver and bone type alkaline phosphatase, and some human serum proteins. Since these tumours produced lactic dehydrogenase 1 but not the other four isozymes of lactic dehydrogenase, this isozyme, like alpha-fetoprotein, seems to be a good marker for the diagnosis and management of cases of endodermal sinus tumour. One of the two tumours produced another fetal antigen or carcinoembryonic antigen in addition to alpha-fetoprotein. These two endodermal sinus tumours, with their various markers in nude mice, will be useful in studies on diagnostic markers.

Alpha-fetoprotein, alpha-1-antitrypsin, and transferrin in gonadal yolk-sac tumours.

Since gonadal yolk-sac tumour in pure form or as a component of mixed germ cell tumour is in the majority of patients highly malignant, its histological recognition is of great prognostic importance. Yolk-sac tumour may assume various different histological guises, which have hitherto caused considerable terminological confusion; the present paper is aimed at correlating these morphological diversities with biochemical features which are consistent with yolk-sac differentiation. Using an enzyme-bridge immunoperoxidase technique, a series of 16 gonadal germ cell tumours with a yolk-sac component were screened for the presence of alpha-fetoprotein, alpha-1-antitrypsin, and transferrin. These proteins, normally produced by human yolk sac, were demonstrable in all the morphological patterns of yolk-sac tumour we have previously described. Six malignant non-germ cell tumours were submitted to the same investigations, and no evidence of the three protein markers was found in five; one tumour, however, an oat cell carcinoma of the bronchus, stained positively for transferrin.

Endodermal sinus tumor arising in the endometrium.

A case of primary endodermal sinus tumor (EST) of the endometrium in a 28-year-old woman is described. EST has been reported to arise in several extragonadal sites, but to the authors' knowledge this is the first documented instance of origin in the endometrium. The histologic study is verified by the detection of alpha-fetoprotein in the tumor by an immunoperoxidase-peroxidase-antiperoxidase technique reported here. Displaced germinal cells, abnormal ovum, and residual fetal tissues are considered as possible origins of the neoplasia.

Mesonephroid carcinoma of the ovary. A clinicopathologic, histochemical, and electron microscopic study.

Eighteen patients with mesonephroid ovarian carcinoma were investigated. Typical findings for the mesonephroid tumors were abundant extracellular an some intracellular neutral mucin mixed with sulfate and carboxyl groups, and large amounts of glycogen, especially in clear cells. The latter observation is considered to be an important aid in distinguishing them from other epithelial ovarian carcinomas. Some cells contained intracellular cysts that were covered with stubby microvilli similar to those found on the lumenal surfaces of the larger cysts in the tumors. Simultaneous estrogenic endometrial activity in the post-menopausal patients was frequently observed. The significance of this observation is discussed.

Value of tumor markers in the treatment of endodermal sinus tumors and choriocarcinomas in the pineal region.

A case of embryonal carcinoma in the pineal region of a 17-year-old boy is presented. The tumor included elements of choriocarcinoma and endodermal sinus tumor, and the use of human chorionic gonadotropin and alpha-fetoprotein as tumor markers is discussed. The markers were demonstrated both within the tumor and in the cerebrospinal fluid (CSF) and blood. The patient was treated with a postoperative program of irradiation and cancer chemotherapy, and at follow-up examination 20 months after operation no signs of residual tumor were present. It is suggested that human chorionic gonadotropin and alpha-fetoprotein should be measured in the blood and CSF before the treatment of midline tumors.

Gonadal endodermal sinus (yolk sac) tumor with pure intestinal differentiation: a new histologic type.

We studied 3 cases of a variant of endodermal sinus tumor (EST) or yolk sac tumor (YST). Two tumors originated in the ovary and one in the testis. The patients had very high levels of serum alpha-fetoprotein (AFP). All three tumors had a characteristic histologic appearance and were composed of acinar structures lined by columnar epithelium with large, immature nuclei. Immunohistochemistry and electron microscopy, including freeze-fracture studies, confirmed that this unusual tumor is one with exclusive intestinal differentiation. We feel that this unique tumor is a pure EST (YST) with exclusive intestinal differentiation.

Cell differentiation in sacrococcygeal teratomas. An immunohistochemical and follow-up study.

The cell differentiation properties of thirty-four sacrococcygeal teratomas (SCT) and their five recurrences were immunohistochemically studied for the expression of different classes of intermediate filament proteins, muscle actin (MA) and S-100 protein. Out of thirty-nine tumors twenty-three were SCTs with only mature tissue elements, seven immature teratomas, five pure endodermal sinus tumors (EST) and four ESTs or embryonal carcinomas (EC) combined with mature components. Cytokeratin positivity was found in all epithelial structures and sometimes also in smooth muscle and primitive mesenchymal cells. An intense cytokeratin immunoreactivity was observed in EC and EST components. Muscle markers, desmin and MA were present in smooth and striated muscle cells. Focal desmin positivity was also found in some epithelial structures in two cases. Glial tissue positive for glial fibrillary acidic protein (GFAP) was found in twenty-eight out of thirty-nine tumors. Some cases with no apparent glial tissue in hematoxylin and eosin staining showed glial differentiation as proved by GFAP positivity. In six out of eleven choroid plexus-like tissues GFAP positive cells were observed. S-100 protein showed an intense distribution of immunoreactivity outside neural tissue, and focal positivity was observed in malignant epithelial structures. Immunohistochemical markers did not reveal any prognostic significance in teratomas. Our findings, however, showed some aberrant features of cell differentiation from normal mature tissue components but closely parallel to those found in normal fetal development.