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.

Increased expression of 25-hydroxyvitamin D-1alpha-hydroxylase in dysgerminomas: a novel form of humoral hypercalcemia of malignancy

Humoral hypercalcemia of malignancy (HHM) is a common paraneoplastic disorder usually associated with increased synthesis of parathyroid hormone-related peptide (PTHrP). Unlike non-cancer forms of hypercalcemia, HHM does not routinely involve increased circulating levels of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Dysgerminomas are a notable exception to this rule, previous reports having described hypercalcemia with elevated serum 1,25(OH)2D3. To investigate the etiology of this form of HHM we have characterized expression and activity of the enzyme that catalyzes synthesis of 1,25(OH)2D3, 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-hydroxylase), in a collection of 12 dysgerminomas. RT-PCR analyses indicated that mRNA for 1alpha-hydroxylase was increased 222-fold in dysgerminomas compared to non-tumor ovarian tissue. Parallel enzyme assays in tissue homogenates showed that dysgerminomas produced fivefold higher levels of 1,25(OH)2D3 compared to normal ovarian tissue. Immunolocalization studies indicated that 1alpha-hydroxylase was expressed by both tumor cells and by macrophages within the inflammatory cell infiltrate associated with dysgerminomas. The immunological nature of the increased 1,25(OH)2D3 production observed in dysgerminomas was further emphasized by correlation between expression of 1alpha-hydroxylase and the endotoxin recognition factors CD14 and toll-like receptor 4 (TLR4). These data suggest that inflammatory mechanisms associated with dysgerminomas are the underlying cause of the increased expression and activity of 1alpha-hydroxylase associated with these tumors. We further postulate that this autocrine/paracrine action of 1alpha-hydroxylase may lead to increased circulating levels of 1,25(OH)2D3 and a form of HHM which is distinct from that seen with PTHrP-secreting tumors.

A case of pediatric ovarian dysgerminoma associated with high serum levels and positive immunohistochemical staining of neuron-specific enolase

A 5-year-old girl presented with a painful abdominal mass. Abdominal magnetic resonance imaging (MRI) showed 3 separate masses. Tumor markers including lactate dehydrogenase (LDH), cancer antigen-125 (CA-125), beta-subunit of human chorionic gonadotropin (beta-hCG) and neuron-specific enolase (NSE) were elevated. At operation, the main tumor arose from the left ovary and was associated with torsion, whereas the other lesions were lymph node metastases. A salpingo-oophorectomy was performed. Histopathologic examination indicated that the tumor was a dysgerminoma. Immunohistochemicallly, the cells were positive for NSE and placental alkaline phosphatase (PALP) but were negative for CA-125, beta-hCG, S-100, glial fibrillary acidic protein, and vimentin. The elevated serum levels of tumor markers improved dramatically after the operation and chemotherapy.

Laboratory markers and germ cell tumors

The International Germ Cell Consensus Classification (IGCCC) of testicular germ cell tumors (TGCT) in 1997 included three serum tumor markers, serum lactate dehydrogenase catalytic concentration (S-LD), serum alpha fetoprotein concentration (S-AFP), and serum human chorionic gonadotropin concentration (S-hCG). The recommendation should be implemented for all patients with TGCT and is also useful for patients with ovarian and extragonadal germ cell tumors. A fourth serum tumor marker for TGCT, S-LD isoenzyme 1 (S-LD-1), is also relevant for TGCT. Patients with seminoma have a raised S-LD-1 more often than a raised S-AFP and S-hCG, whereas patients with nonseminoma have a raised S-AFP more often than a raised S-LD-1 and S-hCG. A new model combining IGCCC and S-LD-1 predicts survival better than previous staging systems. LD-1 is related to a characteristic chromosomal abnormality in all types of TGCT, a high copy number of chromosome 12p. In contrast, AFP and hCG are found mainly in nonseminomatous germ cell tumors and they related to the histologic differentiation of the tumors. The different biologic background for the serum tumor markers may contribute to the difference in their clinical behavior.

Ovarian mixed germ cell tumor composed of dysgerminoma, endodermal sinus tumor, choriocarcinoma and mature teratoma in a 44-year-old woman: case report and literature review

A case of ovarian mixed germ cell tumor in a 44-year-old woman was examined. The tumor was well circumscribed, measured 15 x 11 x 10 cm and appeared solid and partly cystic on the cut surface. Light microscopic examinations revealed that the tumor was composed of four different neoplastic germ cell elements, intermingled with each other. They are: (i) choriocarcinoma, immunohistochemically positive for human placental lactogen (hPL) and human chorionic gonadotropin (hCG); (ii) dysgerminoma, positive for placental alkaline phosphatase; (iii) endodermal sinus tumor positive for alpha-fetoprotein (AFP); and (iv) mature teratoma. Among these histological types, dysgerminoma occupied more than 50% of the neoplasm. The patient was diagnosed as a stage la ovarian mixed germ cell tumor and was subsequently treated with chemotherapy. A second-look laparotomy after completion of chemotherapy revealed no residual tumors in the abdomen and the patient is alive and well 15 months after operation. This is the fourth reported case of ovarian mixed germ cell tumor arising in patients over 40 years old.

Simultaneous detection of all four alkaline phosphatase isoenzymes in human germ cell tumors using reverse transcription-PCR

We have developed a reverse transcription-PCR method that clearly distinguishes between the RNA transcripts of all four alkaline phosphatase (AP) genes. If compared to the methods used up to the present, the main advantages of the reverse transcription-PCR method presented are its specificity and high sensitivity. The germ cell AP and the placental AP, which are the two most closely related AP isoenzymes (98% homology), can clearly be distinguished without any interference by other AP isoenzymes. An enhanced expression of AP isoenzymes has been reported for various tumors. The examination of the pattern of AP isoenzyme expression in a specific tumor and the corresponding tissue of origin enables discrimination between eutopically and ectopically expressed isoenzymes and thus represents an important tool in the elucidation of AP isoenzymes as potential tumor markers. The pattern of AP expression in 15 germ cell tumors, 2 germinal epithelia adjacent to seminoma, 2 cell lines of germ cell tumor origin (Tera-1 and BeWo), and 5 normal testes was studied. In comparison to normal testes, in all seminomatous germ cell tumors eutopic expression of germ cell AP and ectopic expression of tissue-nonspecific AP were demonstrated. In both samples of pure embryonal carcinoma and in the embryonal carcinoma cell line, the transcription of all four mRNAs was shown. These results indicate that the expression of the isoenzymes depends on the degree of differentiation of a tumor and that a simultaneous up-regulation of all AP isoenzymes in all types of germ cell tumors does not exist.

Elevated serum angiotensin converting enzyme levels in metastatic ovarian dysgerminoma

A case of a 32-year-old XY genotype female is described, presenting with mediastinal and abdominal lymphadenopathy and associated with an elevated serum angiotensin I converting enzyme (SACE) level. Lymph node histology showed a malignant dysgerminoma of ovarian origin. Combined chemotherapy led to a radiological regression of the lymphadenopathy and coincided with a decrease in SACE concentration. The authors suggest that SACE may be a marker for disseminated germinoma tumours and may be useful for monitoring treatment.

Lack of evidence for aromatase expression in human ovarian epithelial carcinoma

It is controversial whether ovarian epithelial carcinoma possesses steroidogenic enzymes. We investigated aromatase expression in ovarian epithelial carcinoma, and compared it with the normal ovary and placenta. Samples were obtained from an ovarian carcinoma cell line SK-OV-3, ovarian tumour tissues from four patients with epithelial carcinoma and one patient with dysgerminoma. Aromatase enzymatic activity was measured in microsome fractions by quantitating 3H2O released from [1-3H] androstenedione and [3H]oestrone converted from [1,2,6,7-3H] androstenedione. Aromatase messenger ribonucleic acid (mRNA) was determined by reverse transcription-polymerase chain reaction (RT-PCR) using oligonucleotide primers synthesized according to the published human aromatase gene sequence. No aromatase activity was detected in either of two mucinous cystadenocarcinoma specimens or in SK-OV-3 cells, while aromatization proceeded with apparent Michaelis-Menten kinetics in the normal ovaries and placentas. The apparent Km value was 200 nmol/L for the ovary. Aromatase mRNA was detected in dysgerminoma, and the normal ovary and placenta, but not in any of three mucinous cystadenocarcinoma specimens, one serous cystadenocarcinoma specimen and SK-OV-3 cells. These results for both enzyme activity and gene expression suggest that the human ovarian epithelial carcinoma lacks aromatase. The demonstration of absence of aromatase gene expression raises the possibility that aromatase activity in ovaries bearing epithelial carcinoma may be associated with hyperplastic stromal rather than tumour cells.

Differential expression of a human sperm-specific isozyme in seminoma cells transplanted in Scid-nu(str) mice

An isozyme of human sperm-specific lactate dehydrogenase, LDH-X (C4) (EC 1.1.1.27), which is expressed only in differentiated germ cells (spermatozoa, spermatids and primary spermatocytes after midpachytene), appeared in the xenografted tumor cells of human seminoma and its metastatic lesions (lymph node and kidney) in scid (severe combined immunodeficiency)-nude(streaker) double mutant mice, though it was not expressed in the original tumor of the patient. The morphological pattern of seminoma cells also changed in the xenografts and metastatic lesions as in normal spermatogenesis. Thus, the human seminoma cells showed differential expression of the sperm-specific isozyme in parallel with their morphological changes. However, the sperm-specific isozyme disappeared in the mitotically dividing seminoma cells which were newly established from the LDH-X positive xenograft.

Immunopathology of alkaline phosphatase isozymes in seminoma

An immunohistopathological study using monoclonal antibodies for alkaline phosphatases demonstrated placental alkaline phosphatase (PLAP)-like substance in the tumor cells of 11 pure seminomas, 1 seminoma with embryonal carcinoma and 1 seminoma metastasis. Liver alkaline phosphatase (LAP) could also be demonstrated in all seminomas but a third intestinal alkaline phosphatase (IAP) was not demonstrable in any tumor. The PLAP-like substance and LAP had considerable enzyme activities. This provides two tumor markers of seminomas detectable in histopathological specimens.

Glutathione S-transferase expression in the human testis and testicular germ cell neoplasia

Glutathione S-transferase (GST) isoenzyme expression is altered in a variety of neoplasms and the enzymes are implicated in metabolism of carcinogens and resistance to drugs, including cisplatin. We have studied GST Alpha, Pi, Mu and microsomal isoenzyme expression by immunohistochemistry in normal and cryptorchid testes, intratubal germ cell neoplasia (ITGCN), seminoma and non-seminomatous germ cell tumours. In 16 stage II-IV malignant teratoma intermediate (MTI) both orchidectomy and post-treatment residual surgical masses were studied. All four isoenzymes were strongly expressed in Leydig and Sertoli cells. GST Pi was absent from normal spermatogonia but strongly expressed by the neoplastic germ cells of ITGCN and seminoma. GST Pi was strongly expressed in all elements of teratoma, irrespective of differentiation. There were no qualitative differences in expression between primary and post-chemotherapy metastases. GST Alpha expression in teratoma correlated with epithelial differentiation. GSTs may be important in normal spermatogenesis and protection of germ cells from teratogens and carcinogens. They may have a role in testicular tumour drug resistance but this role is not well defined. GST Pi is a new marker for ITGCN.

Alternating cycles of PVB and BEP in the treatment of patients with advanced seminoma

33 patients (median age 39 years) with advanced seminoma were treated with 4 courses of alternating cisplatin-containing chemotherapy PVB/BEP (cisplatin, vinblastine and bleomycin; bleomycin, etoposide and cisplatin). Patients were classified as stage IIC (n = 7), IID (n = 9), III (n = 13) and IV (n = 4). 8 had had prior radiotherapy; 9 had an elevated beta human chorionic gonadotropin (beta HCG). 30 patients were evaluable for response and 33 for toxicity. During chemotherapy 3 patients died, 1 due to malignant disease, another due to a cardiac arrest, and 1 patient of a bleomycin pneumonitis. 13 (43%) had a complete remission and 17 (57%) had a clinical partial remission (residual radiographic mass). At a median follow-up of 28 months (range 16-88), 3 patients relapsed, 6-8 months after entry. After completion of therapy there were 2 deaths, 1 due to bleomycin pneumonitis and 1 neither tumour nor treatment related. 26 of 33 (79%) patients achieved a continuously disease-free status. Leucocytopenia and thrombocytopenia of WHO grade 3/4 occurred in, respectively, 32/33 (97%) and 20/33 (61%) of the patients. This study shows that alternating PVB/BEP in this group yields comparable response rates with non-alternating schedules but at the expense of considerable toxicity.

Significant improvement of the survival of seminoma cells in vitro by use of a rat Sertoli cell feeder layer and serum-free medium

Seminoma cell lines, essential to the study of the biology of seminoma, do not exist. Tissue culture conditions for establishing such cell lines have to be developed. Under conventional culture conditions, seminoma cells usually die within the first 3 days after plating. The enhanced survival of rat gonocytes when cocultured with rat Sertoli cells in serum-free medium suggests that seminoma cells, the neoplastic counterparts of gonocytes, might benefit from the same conditions. Indeed, when cocultured with rat Sertoli cells in a serum-free medium, viable seminoma cells could be demonstrated on the 11th day of culture. This result is a significant improvement over the results with conventional methods.

An assessment of combined tumour markers in patients with seminoma: placental alkaline phosphatase (PLAP), lactate dehydrogenase (LD) and beta human chorionic gonadotrophin (beta HCG)

We have assessed the tumour markers placental alkaline phosphatase (PLAP), lactate dehydrogenase (LD), and human chorionic gonadotrophin (beta HCG) using 2,000 serum samples from 286 patients with seminoma. The ROC curves show that no one marker performs adequately for the detection of disease either at initial staging or during follow-up. We used a Markov model heuristically to devise strategies, in which marker results were assessed in combination, which might be useful in clinical practice. We found that the best strategy was to consider a test result abnormal only if either the beta HCG was greater than 6 Ul-1 or the LD was greater than 400 U l-1 and the PLAP level was greater than 60 U l-1. This will detect about 50% of patients with disease and the false-positive rate is 2%. In practical terms this means that PLAP need only be estimated in patients whose beta HCG is less than 6 IU l-1 and whose LD is greater than 400 U l-1.

Cerebrospinal fluid placental alkaline phosphatase in the intracranial germinomas: results of enzyme antigen immunoassay

The authors investigated the placental alkaline phosphatase (PALP) activity in cerebrospinal fluid (CSF) by enzyme-antigen immunoassay using polyclonal antibody as a marker for intracranial germinomas in 17 patients with germ cell tumors and 20 with other disorders. The detection limit of PALP activity was 0.072 optical density units equivalent to 5.9 ng/ml. Five of nine germinomas demonstrated high CSF PALP activities before treatment. These high PALP activities became undetectable following radiation therapy. The other tumors were small or had no CSF contact. CSF PALP activity is a useful tumor marker for pure germinomas.

Characterization of seminoma-derived placental-like alkaline phosphatase

Characteristics of placental-like alkaline phosphatase (PLAP-like enzyme) in seminoma was studied. By use of lectin affinity chromatography, PLAP-like enzyme in seminoma revealed extra sugar chains compared to placental alkaline phosphatase (PLAP), indicating heterogeneity of the carbohydrate moiety. However, the glycosylation patterns were found to be essentially similar between seminoma and normal testis. On isoelectric focusing, differences in migration patterns were revealed between seminoma-derived and normal testis-derived PLAP-like enzyme as well as between PLAP-like enzyme and PLAP. The differences in charge were mainly due to differences in sialylation of the molecules. The complex pattern of PLAP-like enzyme from seminoma on isoelectric focusing was not altered by neuraminidase treatment, indicating a considerable charge heterogeneity within the population of the enzyme molecules from the tumor.

[Serum ribonuclease in patients with malignant tumor of the ovary]

The clinical significance of serum ribonuclease (RNase) was studied in patients with malignant tumor of the ovary, and the result was compared with serum sialic acid (SA). Serum RNase and SA level were determined in 190 women consisting of 35 normal women, 34 patients with ovarian cancer, 39 patients with other malignant gynecological tumors, 38 ovarian cancer patients with clinical remission after treatment and 44 patients with benign gynecological tumor. The sensitivity of serum RNase was 82.4% in the diagnosis of malignant tumor of the ovary. Serum RNase was positive in 42.9% of patients with minimal residual tumor and 88.9% those with residual tumors greater than 2 cm in diameter. Serum RNase assay is a simple, rapid and reliable method useful in monitoring the course of disease.

Identification and characterization of alkaline phosphatase isozymes in human colorectal adenocarcinomas

Using alkaline phosphatase isozyme-specific immunocatalytical assays, the content of isozymes was determined in normal mucosas and adenocarcinomas from human colon or rectum. Tumor levels of both the tissue (liver)-unspecific and the placental-like alkaline phosphatase (PLAP-like) were elevated compared to normal mucosas of the same patients. Such elevations have been reported previously, particularly in seminomas and ovarian tumors. In several tumors, moreover, the intestinal isozyme was expressed in lesser amounts than in the adjacent mucosa. The present results indicate that the activation of two of the phosphatase isozymes, including expression of the typical germ cell line phosphatase (the PLAP-like isozyme), may occur even in nongonadal tumors. This may reflect an induction pattern of phosphatase isozymes, with implications for malignant transformation also in other tumors.

Isoenzymes of alkaline phosphatases in seminomas. An immunohistochemical and biochemical study

Placental alkaline phosphatase (the PLAP-like isoenzyme) and liver alkaline phosphatase (LAP) were demonstrated immunohistochemically by use of monoclonal antibodies in the tumor cells of twelve seminomas and one seminoma metastasis. Intestinal alkaline phosphatase (IAP) was not found. The PLAP-like and LAP enzymes showed high catalytic activities compared to normal testis. This is the first occasion that LAP has been demonstrated by immunochemistry in seminoma cells. The results suggest that demonstration of these tumor enzymes may be useful markers for seminomas in histopathological specimens.

[Serum and tissue levels of placental alkaline phosphatase in patients with testicular tumor]

Placental alkaline phosphatase (PLAP) levels in sera and tissues from 40 patients with testicular tumor were measured using a monoclonal immuno-catalytic assay. The mean value of the PLAP levels of seminoma tissues was found to be 92-fold higher than that of normal testes, being significantly high compared with that of non-seminoma tissues. The mean value of the serum PLAP levels from patient's with seminoma was also significantly higher than that from patients with non-seminoma. In 2 groups of seminoma and mixed type tumor containing seminoma and non-seminoma components, the PLAP levels of tissues from patients who had high levels of the serum PLAP (greater than or equal to 100 mKAU) were significantly higher than those from patients who had normal serum PLAP levels (less than 100 mKAU). In the seminoma or mixed type tumor groups, the serum PLAP levels of all patients who had high levels before treatment decreased to within a normal range after orchiectomy with or without chemotherapy or radiation therapy. We conclude that PLAP seems to be an useful tumor marker for the diagnosis and the monitoring of response to treatment in patients with seminoma.

Enolase isozymes in seminoma

We determined concentrations of alpha and gamma-enolases in normal testis and in seminoma tissues by enzyme immunoassay. Concentrations of alpha-enolase were 4,170 +/- 2,040 ng/mg protein in normal testis (n = 8) and 8,140 +/- 4,480 ng/mg protein in seminoma (n = 8). Concentrations of gamma-enolase in seminoma (460 +/- 571 ng/mg protein) were significantly higher than those of normal testis (59 +/- 15 ng/mg protein). Immunohistochemistry showed positive tumor cells for gamma-enolase in 6 of 8 seminoma cases (75%). Serum gamma-enolase levels were elevated (greater than 6.0 ng/ml) in 9 of 12 patients (75%) with seminoma: 60% of stage I, and 100% of stages II and III. In 10 patients treated by surgical excision and chemotherapy, serum gamma-enolase was significantly reduced after the treatment. These findings indicate that elevated serum gamma-enolase is derived from enhanced gamma-enolase in seminoma tissues, and that serum gamma-enolase could be a useful biomarker for staging and monitoring clinical course in patients with seminoma.

Placental-like alkaline phosphatase in seminoma

Tumor marker identification in testicular cancer has contributed to early detection and monitoring of non-seminomatous disease. A placental alkaline phosphatase-like (PLAP-like) enzyme derived from seminomas has recently been focused upon as a possible marker for this disease. The biochemistry of the PLAP-like enzyme is reviewed, as well as its occurrence in tissue and sera from healthy persons and patients with testicular cancer.

Enzymatic heterogeneity of seminomas

Heterogeneity of placental-like alkaline phosphatase (PLAP-like enzyme) in seminoma was studied. PLAP-like enzyme from seminoma tissues was separated into three areas with different proportions between tumors, while PLAP and PLAP-like enzymes in normal testes were separated into two areas on the basis of hydrophobicity. By use of lectin affinity chromatography, PLAP-like enzyme in seminoma revealed extra sugar chains compared to PLAP, indicating heterogeneity of the carbohydrate moiety. However, the glycosylation patterns were found to be essentially similar between seminoma and normal testis. On isoelectric focusing, differences in migration patterns of PLAP-like enzyme were revealed between seminoma and normal testis as well as between PLAP-like enzyme and PLAP. The differences in charge were mainly due to differences in sialylation of the molecules. The complex pattern on isoelectric focusing was not altered by neuraminidase treatment, indicating a considerable charge heterogeneity within the population of PLAP-like enzyme molecules from seminoma.

Placental alkaline phosphatase in developing normal and abnormal gonads and in germ-cell tumours

The evolution of the gonads during intra-uterine development has been followed by immunohistochemical demonstration of placental-like alkaline phosphatase (PLAP) at the germ-cell level. PLAP immunopositivity was restricted to the limited period when germ cells were not surrounded by granulosa or Sertoli cells. Abnormal fetuses or neonates presenting with chromosomal anomalies frequently had disorganized gonads where germ cells retained their membrane PLAP immunopositivity. This abnormal immunopositivity is similar to that expressed by abnormal germ cells in testicular in situ carcinoma, in gonadoblastoma (case of 45,XO/46,XY mosaic) and in seminoma. The pattern of positivity for other germ-cell tumours was highly variable. We suggest that in abnormal gonads, dysgenetic or neoplastic, an early embryonic property is retained by abnormal germ cells. Its importance in the process of neoplastic induction remains to be defined.

Analysis of serum placental alkaline phosphatase activity in testicular cancer and cigarette smokers

Serum PLAP/PLAP-like enzymes are elevated in testicular cancer patients and also in heavy smokers. Such elevations were measurable with anti-PLAP polyclonal and monoclonal antibodies, and an antigenic heterogeneity was demonstrated in the circulating enzymes. Thus polyclonal antibody revealed more of tumor PLAP-like antigen while a monoclonal antibody H7 detected PLAP of smokers better. PLAP of smokers and PLAP-like enzyme of cancer (seminoma) patients showed similar characteristics with respect to glycosylation pattern, charge and hydrophobicity. By these properties they were differentiated from PLAP of placenta.

Is placental alkaline phosphatase (PLAP) a useful marker for seminoma?

The usefulness of placental alkaline phosphatase (PLAP) as a tumour marker was assessed in 1578 serum samples from 236 patients with seminoma. Smoking habits were known for all but 7 patients (22 samples). Smoking was associated with significantly higher mean levels of PLAP in disease-free patients (28.8 [S.E. 2.1] U/l vs. 15.9 [1.3] U/l in non-smokers). Mean PLAP levels were higher in patients with active disease (78.6 [23.5] U/l in non-smokers and 47.2 [18.5] U/l in smokers). The median values showed a similar trend. However, there was considerable overlap between the various groups and differences between mean and median values indicated that PLAP values were distributed asymmetrically. The predictive value of PLAP as a tumour marker was consequently much less than superficial inspection of these values might suggest. In 97 patients on surveillance, only 2 out of 11 patients who relapsed had elevated PLAP at the time of clinically detectable relapse. With the upper limit of normal PLAP quoted by our laboratory (35 U/l), specificity and sensitivity were, respectively, 88% and 45% (all patients) and 96% and 47% (non-smokers). The sensitivity and specificity of PLAP were assessed in more detail for a series of threshold values (normal vs. abnormal) with a graphical method. Only in non-smokers did PLAP seem useful and even in this group the positive predictive value of an "abnormal" test may be low; less than 50% in clinically relevant circumstances. Serum PLAP assay cannot usefully stand alone as a marker for seminoma and its routine estimation contributes little to follow-up.

Alkaline phosphatase isozymes in human testicular germ cell tumors, their precancerous stage, and three related cell lines

The four known isozymes of the human alkaline phosphatase (ALP) were detected by isoelectric focusing in extracts of various types of germ cell tumors, three related cell lines, and their precancerous elements (atypical germ cells). In seminoma, placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (PLAP-like) could be separated by isoelectric focusing following isolation by immunoaffinity. The occurrence of both isozymes in seminoma could explain partial heat sensitivity and variation in electrophoretic patterns of the seminoma isozyme frequently observed upon starch gels, in comparison to the normal placental phenotype. The four ALP isozymes are produced not only in germ cell tumors, but already in precancerous tissues. Quantitative analysis showed that the amount of the four isozymes varies in parallel in the tumors tested. Maximal expression was found in seminoma. The relation between ALP gene overexpression and gene amplification by polyploidy of chromosomes 1 and 2 in these lesions is discussed. On the other hand, the ectopic expression of intestinal alkaline phosphatase and PLAP associated with overexpression of PLAP-like in tumor cells as well as in their precancerous stage indicates gene activation by some unknown mechanisms, probably a regulatory process affecting the three tissue-specific ALP genes simultaneously.

[Histochemical study on glutathione S-transferase in patients with testicular tumor]

Tumor tissue and nontumorous tissue of 31 patients with testicular tumor were examined by the peroxidase antiperoxidase (PAP) procedure using the primary antibody against glutathione S-transferase (GST). Histology of primary tumor was classified as seminoma in 10 cases, non-seminoma in 18 (including 2 cases of yolk sac tumor), and malignant lymphoma in 3. Tumorous tissues except one with yolk sac tumor failed to be stained with GST. The seminiferous tubules of the nontumorous testicular tissue had a positive reaction in the infant cases, but not in the adult cases. The degenerated seminiferous tubules involved in the testicular tumors also had a positive reaction in all the cases. Leydig cells had a positive reaction in all the cases. In particular, diffuse Leydig cell's hyperplasia was observed in a case with high serum beta hCG and urinary hCG levels. These data may be relevant in explaining the inherent hypofertility of these patients.

Neuron-specific enolase as a serum marker for immature teratoma and dysgerminoma

Neuron-specific enolase (NSE) was measured with an enzyme-immunoassay in sera from 54 patients with malignant (24 cases) and benign (30 cases) germ cell tumors of ovarian origin. Serum NSE contents were clearly raised above control value (greater than 10 ng/mg) in 4 of 8 patients with immature teratomas and 5 of 6 with dysgerminomas. NSE was also measured in nine cell lines of germ cell tumors. Among these cell lines, high NSE contents were detected in the cell extracts and culture supernatants from PA-1 and Tera-II lines. In immunohistochemical study, widespread positive staining for NSE was shown in dysgerminomas, whereas the immunostaining was confined to neural elements in both an immature teratoma and xenograft tumors derived from PA-1 and Tera-II lines in nude mice. These findings suggest that serum NSE measurements are of diagnostic value not only for immature teratomas but also for dysgerminomas.

Hydrophobicity and lectin affinity of alkaline phosphatase isozymes in seminoma and normal testis

Isozymes of alkaline phosphatases (ALP) in seminoma and normal testis were separated by use of high-performance liquid chromatography and a TSK-gel phenyl-5PW column. The tissue-nonspecific (liver) ALP (LAP) was the dominating isozyme, consisting of more than 90% ALP activity. The placental ALP (PLAP)-like enzyme contributed to 4-8% of the total ALP activity. The intestinal isozyme (IAP) could not be identified. The glycosylation patterns of the isozymes were studied using concanavalin A (Con A) affinity chromatography and batch elution with competing sugar. All PLAP activity in placental extracts and LAP activity in liver extracts was bound to Con A-Sepharose. In the tumor extracts, only 50-70% of the PLAP-like enzyme and 20-50% of the LAP activity from seminomas were bound to Con A-Sepharose. A similar binding pattern of the PLAP-like enzyme and LAP was also seen in the normal testes. This variability in Con A reactivity with PLAP or the PLAP-like enzyme was also reflected in serum of seminoma patients and of pregnant women. Thus, ALP expressed in seminoma has different lectin affinity characteristics compared with the same isozyme from placenta and liver, but almost identical to ALP in the normal testes. These findings imply that the PLAP-like enzyme and LAP in the testis can be discriminated from PLAP of placenta and LAP of liver by carbohydrate lectin affinity. It also supports the concept that the increased amounts of ALP in seminomas result from the enhanced eutopic expression of enzymes normally expressed in the testis.

Electrophoretic heterogeneity of alkaline phosphatase isozymes in seminoma and normal testis

Electrophoretic patterns of seminoma- and normal-testis-derived alkaline phosphatase isozymes, the placental alkaline phosphatase (PLAP)-like enzyme and the tissue-nonspecific (liver) alkaline phosphatase (LAP), were studied on starch gel and isoelectric focusing (IEF). Different migration patterns of the PLAP-like enzyme were observed with respect to both seminomas and normal testes on starch gel electrophoresis. On IEF, seminomas showed different staining patterns among different tumors; however, a common main activity was focused at pIs of 4.3-4.6, corresponding to pIs of PLAP. Normal testes showed two enzyme-staining regions, at pIs of 4.1 and 5.0-5.2, which were discriminated from pIs of PLAP and the PLAP-like enzyme in seminoma. The PLAP-like enzyme in seminoma was differentiated from PLAP by digestion with neuraminidase. Neuraminidase treatment simplified the distribution patterns of the PLAP-like enzyme in normal testis, but did not alter the pattern of microheterogeneity in seminoma. Two factors other than sialylation, namely structural modification of the carbohydrate moiety and variation of hydrophobicity, were shown to contribute to the microheterogeneity of the PLAP-like enzyme in seminoma. LAP in seminoma and in normal testis also showed marked electrophoretic heterogeneity and differences in pI distributions from LAP of liver. However, the migration patterns after desialylation were very similar to each other. The findings imply that electrophoretic heterogeneity demonstrated in LAP in seminoma and in normal testis is caused by a difference in sialic acid content in the molecule, and the heterogeneity of the PLAP-like enzyme in seminoma is considerable.

Serum lactic dehydrogenase and its isoenzymes in patients with ovarian dysgerminoma

Lactic dehydrogenase (LDH) is a glycolytic enzyme that may be elevated in the serum of patients with gonadal and extragonadal germinomas. In this report, a case of unilateral ovarian pure dysgerminoma with remarkably elevated levels of serum LDH is presented. After complete excision of the tumor, serum LDH levels promptly returned to normal levels. Although an electrophoretic pattern of serum LDH isoenzymes was within normal limits pre-operatively, an increase in LDH-1 and 2 was found 1 week after operation. Seventeen additional examples of ovarian dysgerminomas with elevated serum LDH levels have been reported in the English literature including five cases who had high levels of two fast fractions of LDH. These data suggest that serum LDH levels and its isoenzymes pattern are useful tumor markers for diagnosis and post-therapy surveillance in patients with ovarian dysgerminomas.

Elevated lactate dehydrogenase isoenzyme 1 as a tumour marker in patients with germ cell testicular tumours

In a series of 50 patients with testicular tumours evaluated prior to orchidectomy, 12 out of 19 with pure seminoma and seven out of 31 with non-seminomatous or mixed seminomatous and non-seminomatous germ cell tumours had elevated plasma lactate dehydrogenase isoenzyme 1 concentrations. In contrast, seven of the 19 seminoma patients had elevated serum human chorionic gonadotrophin (hCG) concentrations and 25 of the 31 non-seminomatous and mixed seminomatous and non-seminomatous germ cell tumour patients had elevations of hCG and/or alpha-fetoprotein. Using these three markers, 12 out of 19 seminoma patients and 27 out of 31 non-seminomatous or mixed seminomatous and non-seminomatous tumour patients were positive for one or more of these tumour markers.

Microsomal aromatase in testicular tumour tissue: increased activity in choriocarcinoma compared to embryonal carcinoma

Microsomal aromatase activity was assayed in testicular tumour tissue from one patient with choriocarcinoma and two patients with embryonal carcinoma. In the microsomal fractions of tumour tissue conversion of 3H-testosterone and 3H-androstenedione to 3H-17 beta-estradiol and 3H-estrone was measured. Aromatase activity was markedly increased (8-fold) in choriocarcinoma compared to embryonal carcinoma. In the choriocarcinoma patient, high HCG-levels measured in serum and the increased aromatase activity in the tumour with resulting elevated estrogen levels in serum seem to be responsible for the decreased production of androgen in this type of tumour.

Placental alkaline phosphatase immunohistochemistry of intratubular malignant germ cells and associated testicular germ cell tumors

Two hundred three testicular germ cell tumors were studied immunohistochemically for the presence of placental alkaline phosphatase (PLAP). Special emphasis was placed on the pattern and incidence of positive staining of intratubular malignant germ cells (ITMGCs) adjacent to tumors. 99% of cases with adjacent ITMGCs showed a positive staining reaction in some or all IT-MGCs present. Other germ cell elements showed at least a focal positive staining reaction in the following proportions: seminomas, 96%; embryonal carcinomas, 96%; yolk sac tumors, 25%; mature teratomas, 5%; immature teratomas, 4%; choriocarcinomas, 45%; and syncytiotrophoblasts, 43%. The staining pattern for seminomas tended to be diffuse, whereas for embryonal carcinomas the staining pattern was more focal. Yolk sac tumors stained inconsistently for PLAP and a positive reaction was limited to a small percentage of cells. Syncytiotrophoblasts, singly or in choriocarcinomas, also showed variable positivity. These results corroborate the fact that PLAP is a sensitive marker for ITMGC, seminoma, and embryonal carcinoma.

Placental alkaline phosphatase as a tumor marker for primary intracranial germinoma

A sensitive enzyme-linked immunosorbent assay (ELISA) was used in a retrospective study of placental alkaline phosphatase (PLAP) levels in serum, cerebrospinal fluid (CSF), and intratumoral cyst fluid in primary intracranial germinoma. The ELISA showed no cross-reactivity with intestinal alkaline phosphatase except in very high concentrations, after samples had been heat-treated. Three patients with germinoma were studied for serum PLAP levels and in all the levels were elevated (3.78, 0.52, and 2.11 IU/liter). Two of the germinoma patients were studied for PLAP levels in the CSF, and both had elevated levels (0.83 and 9.83 IU/liter). The intratumoral cyst fluid in one case of germinoma was tested for PLAP and the level was found to be very high (603 IU/liter). These PLAP levels decreased concomitantly with the reduction in tumor size during irradiation. Serum PLAP levels were measured in 40 control adult male individuals and in the CSF of 20 nonpregnant patients with subarachnoid hemorrhage. The upper normal limits were 0.20 and 0.11 IU/liter in the serum and the CSF, respectively. All PLAP levels measured in the serum of patients with various brain tumors were 0.18 IU/liter or less. This study strongly suggests that PLAP is a clinically useful tumor marker for primary intracranial germinoma.

Isoenzymes of alkaline phosphatase in germinoma cells

Utilizing 18 germinomas, the characteristics of isoenzymes of alkaline phosphatase (ALP) in germinoma cells were examined by light and electron microscopic enzymohistochemical and immunohistochemical techniques and biochemical methods including inhibition tests, electrophoresis and electrosyneresis. ALP in germinoma cells was generally located on the cell surface. In a few germinoma cells, however, ALP was seen not only on the cell membrane but also in the endoplasmic reticulum. Enzymohistochemically as well as biochemically, ALP in germinoma cells was little sensitive to L-phenylalanine, moderately sensitive to L-homoarginine and somewhat resistant to heat in its inhibition tests. Immunohistochemical examinations and electrosyneresis showed the presence of the placental type of ALP in germinoma cells and biochemical analyses revealed that the heat-stable component of ALP in germinoma cells was consistent with the D-variant of the placental type of ALP. Therefore, germinoma cells possessed mixed isoenzymes of ALP, consisting mainly of the liver/bone type and a small amount of D-variant of the placental type on the cell surface. The prominent expression of ALP in germinoma cells may be due to the enhanced expression of gonadal genes active in the germinoma genome.

Seminoma-derived Nagao isozyme is encoded by a germ-cell alkaline phosphatase gene

A full-length placental alkaline phosphatase (PLAP) cDNA was used to identify and clone the PLAP-like Nagao isozyme gene from human genomic libraries. The entire nucleotide sequence of the gene reveals the existence of 11 exons interrupted by 10 small introns (76-427 base pairs). Putative regulatory sequences have been identified in the promoter regions as well as dispersed in the introns. The deduced amino acid sequence of the Nagao isozyme indicates that the mature molecule is composed of 513 amino acids, of which 12 residues are different from the sequence of PLAP (98% homology). A sequence derived from exon III of the Nagao isozyme gene was used to synthesize a peptide (NH2-Lys-Leu-Gly-Pro-Glu-Thr-Phe-Leu-Ala-COOH) that contains two mutations with respect to the corresponding PLAP sequence. This peptide elicited rabbit polyclonal antibodies that reacted specifically with the seminoma Nagao isozyme but not with PLAP in electrophoretic transfer blots. These results indicate that the tumor, and possibly the normal testis, Nagao isozyme is encoded by a gene referred to as germ-cell alkaline phosphatase gene that differs from the PLAP gene expressed by syncitiotrophoblastic cells.

Angiotensin-I-converting enzyme in germinomas

Angiotensin-I-converting enzyme (ACE) was detected in 18 germinomas, both of testicular or extratesticular localization, and studied by immunohistochemical methods using specific polyclonal antibodies and by enzyme activity measurements. ACE was also detected in normal human germ cells. On the other hand, it was not present in other types of testicular tumors. Biochemical studies and immunohistochemical findings suggest that at least part of the enzyme is membrane bound. Plasma ACE levels appeared to be normal, indicating that measurement of plasma ACE levels in germinomas would be of little help for the diagnosis and follow-up of patients. However, the apparent specificity of ACE detection in germinomas among germ cell tumors might help in histologic diagnosis, especially for tumors of extragonadal localization.

Patterns of seminoma tissue markers and deletions

Seminomas and control tissues were analyzed for several tumor markers. Very high levels of placental alkaline phosphatase (PLAP)-like enzyme levels were found in all 18 seminomas studied. The majority of the seminomas were of phenotype I, thus differing from palcental PLAP. The mean amount of enzyme protein as measured by monoclonal antibodies, was 100 times higher than in non-malignant tissues and 10 times lower than in placental tissue. The specific enzymatic activity in seminomas was about half of that observed in placenta. Similarly, the specific activity of PLAP-like enzymes in sera of patients with seminoma was only about half of that found in pregnancy sera. HCG was strongly elevated in 3 seminomas, but not obviously related to PLAP. Thirteen of the 17 pure seminomas had HCG over 100 IU/g, which was not seen in normal testes. Liver alkaline phosphatase (LAP) and intestinal alkaline phosphatase (IAP) were high in seminomatous tissues, the mean increases being 60-fold and 20-fold, respectively. The highest IAP levels were found in 2 yolk-sac tumors. Ferritin was moderately elevated in seminomas, but high in several control tissues. Carcinoembryonic antigen (CEA) was not elevated and alpha-fetoprotein (AFP) was not detected at all in pure seminomas. A decrease in carbohydrate antigen 50 (CA-50) content was noted in seminomas as compared to normal testes, yolk-sac tumors and choriocarcinomas. Defects in tumor-related enzymes may account for increase of PLAP and decrease of CA-50.

Identification of testicular atypical germ cells by an immunohistochemical technique for placental alkaline phosphatase

The identification of atypical testicular germ cells is often difficult by by routine histologic examination. By immunohistochemical detection of placental alkaline phosphatase (PLAP) and by periodic acid Schiff staining of glycogen, atypical germ cells were easily identified in testicular samples. Forty-one fetal and adult testes were used for a preliminary study, and 121 testes from infants and adults with either cryptorchidism or germ cell tumors were studied for the presence of atypical germ cells. Two types of clear germ cells were differentiated histochemically, and one with PLAP-positive cell surfaces and glycogen-rich cytoplasm was considered to be atypical. The alkaline phosphatase of atypical germ cells appeared to be similar to that found in a few germ cells of early fetal testes. The atypical germ cells seemed to be multi-potential malignant cells capable of developing not only into seminoma but also into other germ cell tumors. Only in yolk sac tumor of infants were the atypical germ cells absent from tumor-adjacent seminiferous tubules.

Serum neuron-specific enolase. A marker for responses to therapy in seminoma

Neuron-specific enolase (NSE) was evaluated as a serum marker in 105 patients with testicular cancer and compared with the established tumor markers alphafetoprotein (AFP) and human chorionic gonadotropin (HCG). Increased serum NSE activity was measured in eight of 11 (73%) patients with metastatic seminoma. Serum NSE concentrations fell to within the normal range following chemotherapy. Localization of NSE in seminoma cells was demonstrated immunohistochemically. Only six of 40 (15%) patients with metastatic nonseminomatous germ cell tumors showed elevated serum NSE levels. AFP and HCG were both positive in 70% of patients in this group, and NSE determination gave no additional information. Serum NSE concentrations were normal in 53 of 54 testicular cancer patients after orchiectomy and there was no evidence of metastatic disease; only one had borderline NSE levels, indicating the specificity of serum NSE determination. NSE is a new marker of seminoma and its measurement may be of clinical value in monitoring chemotherapy in patients with metastatic seminoma.

Isolation and purification of placental type alkaline phosphatase from a seminoma

An alkaline phosphatase (EC 3.1.3.1) of the placental type was isolated from a seminoma type of human testicular cancer tissue and was purified to homogeneity by sulfate-mediated chromatography on a column of Cibacron Blue Sepharose 4B. The purified enzyme had a specific activity of 40.6 kU per gram of protein and was obtained in a yield of 37%. The purification procedure used was simple and economical, and may be used to purify alkaline phosphatase isoenzymes from other cancer tissues. This is the first report of the purification of the enzyme in seminoma. Inhibition studies suggest that this enzyme is a Nagao variant rather than the Regan type reported in several cancer tissues.

Lactate dehydrogenase as a marker for testicular germ-cell tumours

One hundred and eighty-four patients with testicular germ-cell tumours, 92 with seminoma and 92 with non-seminomatous germ-cell tumours (NSGCT) had total lactate dehydrogenase (LD) assay performed at the time of initial staging following orchidectomy. The proportion of patients with elevated plasma LD and the mean plasma LD increased with advancing stage and increasing tumour bulk for both seminoma and NSGCT. Of patients receiving cytotoxic chemotherapy, 87.5% with seminoma and 63% with NSGCT had elevated plasma LD with subsequent levels reflecting regression or progression of disease. Elevated plasma LD levels were seen in four of seven seminoma, and in 18 of 30 NSGCT patients relapsing after primary treatment. The LD assay provides useful information, and complements the routine measurement of alphafetoprotein (AFP) and beta human chorionic gonadotrophin (beta hCG) in the management of patients with testicular germ-cell tumours.

Phenotypes of placental-type alkaline phosphatase in seminoma sera as defined by monoclonal antibodies

PLAP-like enzymes could be detected in serum of patients with primary testicular tumors, in particular seminomas. The use of a panel of monoclonal antibodies (MAbs) permitted typing into 6 different testicular serum phenotypes, of which one appeared similar to a placental type (II) and 2 have not been previously described. Most tumor sera belonged to type I, as described for seminoma tissues. With a more advanced tumor the mean serum PLAP-like levels increased. After operation, after radiotherapy or with no evidence of disease lower or non-detectable enzyme levels were found. In typing the tissue PLAP-like antigen in serum of the same patient or sera from recurrences of a seminoma in the same patient, the same phenotypes of PLAP-like antigen were usually but not always found. None of the 6 phenotypes appeared to confer a poorer prognosis. We conclude that the expression of PLAP-like antigen is eutopic and is enhanced by testicular malignancy, especially in seminoma cells.