Genetic aspects of testicular germ cell tumors

Testicular Germ Cell Tumor (TGCT) is the most common malignant tumor in young Caucasian men with an annual increase of 3-6% in the past 50 years. Data in the literature indicate that both environmental and genetic factors acting on the primordial gonocyte/gonocyte are implicated in the etiopathogenesis of this tumour. Genetic linkage and genome-wide analyses did not reveal a major gene effect so far, implying that multiple loci must contribute to the development of TGCTs. Only one significant genetic risk factor has been reported, the so called gr/gr deletion of the Y chromosome which still request further confirmation by independent studies. On the other side, the analysis of somatic genetic changes through mutation and genome imbalance analyses and expression profiling has just began to unravel the complex interaction of multiple pathways involved in TGCTs. This review focuses on genetic factors (both genomic and somatic) involved in the etiology, progression and treatment sensitivity of TGCTs.     

Distinction of nephroblastomas from other childhood tumors using antibodies to intermediate filaments

Ten nephroblastomas were investigated by antibodies to intermediate filaments. In seven cases, which in light microscopy were characterized by the presence of blastema and tubules, immunofluorescence microscopy with IF-specific antibodies reveals expression of cytokeratin and vimentin in blastema cells, while tubules were only labelled by the cytokeratin antibodies. This result was independent of whether the conventional cytokeratin antibody or monoclonal antibodies specific for cytokeratin 18 were used. Stroma cells were vimentin-positive. In two cases nephroblastomas were undifferentiated and also lacked tubuli formation. In both these tumors blastema cells were vimentin-positive and cytokeratin-negative. Finally one case of clear cell sarcoma of the kidney could only be labelled by the vimentin antibody. Thus antibodies to intermediate filaments seem to be useful tools to distinguish nephroblastomas from neuroblastomas or rhabdomyosarcomas, especially in cases of metastasis.     

Pathobiology of testicular germ cell tumors: views and news

Human germ cell tumors (GCTs) are a heterogeneous group of neoplasms. They can occur in different anatomic locations, predominantly in the gonads (both ovary and testis) and in the midline of the body, including the retroperitoneal, mediastinal and hypothalamus/pineal gland regions. This distribution has been related to the migration routefollowed by primordial germ cells from the yolk sac to the genital ridge. The clinical behavior of these tumors depends on the sex of the patient, the age at clinical presentation and the histology of the tumor, Within the testis, three groups of GCTs can be distinguished; (I) yolk sac tumors and teratomas of neonates and infants; (II) seminomas and nonseminomas of adolescents and adults, the so-called testicular germ cell tumors; and (III) spermatocytic seminomas. This review discusses the histology, epidemiology and chromosomal constitution of GCT, in particular of the seminomas and nonseminomas of the adult testis, including their precursor, carcinoma in situ. In addition, the available data on the molecular basis of treatment sensitivity and resistance of GCT are reviewed.     

Histogenesis of Ewing's sarcoma. An evaluation of intermediate filaments and endothelial cell markers

Four cases of Ewing's sarcoma, three in bone and one from an extraskeletal site, were studied immunohistologically using monospecific antibodies against intermediate filament proteins of keratin, vimentin, desmin and neurofilament types. All cases were also evaluated for the presence of Factor VIII-related antigen (FVIIIR:Ag) and for the binding of Ulex europaeus I lectin (UEA I), both of which are endothelial markers. In all cases the tumor cells contained vimentin but not keratin, desmin or neurofilaments. The tumor cells could not be decorated with either anti-FVIIIR:Ag or UEA I, whereas the vascular endothelium was positive for both markers. The vimentin-positivity indicates a mesenchymal derivation of Ewing's sarcoma, while the lack of endothelial markers argues against the proposed endothelial origin of this tumor.     

Ultrastructural localization of hCG in the placenta and in testicular germ cell tumors

Human chorionic gonadotrophin(hCG)-producing cells in the human placenta and in testicular germ cell tumors have been investigated by ultrastructural immunohistochemistry using labeled Fab'fragments of anti-hCG-alpha and anti-hCG-beta. Most reaction products were demonstrated in the rough endoplasmic reticulum (rER) and perinuclear spaces of syncytiotrophoblastic giant cells ( STGC ) occurring in embryonal carcinomas and in syncytial cells observed in choriocarcinomas and in normal placenta. The rER of placental and choriocarcinomatous syncytial cells was highly developed and invariably showed a positive reaction. However, the rER of STGCs varied both with regard to its degree of development and its immunoreactivity with hCG. Localization of hCG in the Golgi apparatus and in cytoplasmic granules was indefinite. Mononuclear cells reacting positively with anti-hCG-alpha or -beta were also demonstrated. Cytotrophoblast-like cells which failed to react with anti-hCG-alpha or -beta were noted adjacent to sTGCs and the significance of these cells is discussed.     

Effects of N-acetylcystein on bleomycin-induced apoptosis in malignant testicular germ cell tumors

Oxidative stress has been shown to induce apoptosis in cancer cells. Therefore, one might suspect that antioxidants may inhibit reactive oxygen species (ROS) and prevent apoptosis of cancer cells. No study has been carried out so far to elucidate the effects of N-acetylcysteine (NAC) on bleomycin-induced apoptosis in human testicular cancer (NCCIT) cells. We investigated the molecular mechanisms of apoptosis induced by bleomycin and the effect of NAC in NCCIT cells. We compared the effects of bleomycin on apoptosis with H₂O₂ which directly produces ROS. Strong antioxidant NAC was evaluated alone and in combination with bleomycin or H₂O₂ in germ cell tumor-derived NCCIT cell line (embryonal carcinoma, being the nonseminomatous stem cell component). We determined the cytotoxic effect of bleomycin and H₂O₂ on NCCIT cells and measured apoptosis markers such as caspase-3, caspase-8, and caspase-9 activities and Bcl-2, Bax, and cytochrome c (Cyt-c) levels in NCCIT cells incubated with bleomycin, H₂O₂, and/or NAC. We found half of the lethal dose (LD₅₀) of bleomycin on NCCIT cell viability as 120???g/ml after incubation for 72?h. Incubation with bleomycin (LD₅₀) induced increases in caspase-3, caspase-8, and caspase-9 activities and Cyt-c and Bax protein levels and a decrease in Bcl-2 level. Co-incubation of NCCIT cells with bleomycin and 10?mM NAC abolished bleomycin-induced increases in caspase-3 and caspase-9 activities, Bax, and Cyt-c levels and bleomycin-induced decrease in Bcl-2 level. Our results indicate that bleomycin induces apoptosis in NICCT cells and that NAC diminishes bleomycin-induced apoptosis via inhibiting the mitochondrial pathway. We conclude that NAC has negative effects on bleomycin-induced apoptosis in NICCT cells and causes resistance to apoptosis, which is not a desirable effect in the fight against cancer.     

Ultrastructure of human dermal blood vessels with special reference to the endothelial filaments.

The ultrastructure of endothelial cytoplasmic filaments of small blood vessels from the human dermis has been described. The material consisted of biopsies from normal abdominal and thoracic skin and also from the skin of patients with urticaria pigmentosa. Most vessels were surrounded by multiple layers of basal lamina and corresponded to the small venules of the subpapillary dermis. The wall of many vessels was composed by endothelial cells with clear cytoplasm which was rich in filaments and by endothelial cells with a dense cytoplasm which was poor in filaments. Some vessels had walls composed of clear endothelial cells only. The filaments varied in diameter between 80-120 A. Curling, recoiling and whorling of cytoplasmic filaments were obvious in endothelial cells of contracted vessels. Bulging of endothelial nuclei and nuclear indentations were seen in the skin lesion of urticaria pigmentosa. The possibility that the clear endothelial cells which are rich in filaments may be more actively involved in contraction than the dense cells, is discussed.     

A mini-review of familial ovarian germ cell tumors: An additional manifestation of the familial testicular germ cell tumor syndrome

Introduction While testicular germ cell tumors (TGCTs) are the most common malignancy in young men, germ cell tumors in women are uncommon. Familial clustering, epidemiologic evidence of increased risk with family or personal history of TGCT, and associations with genitourinary tract anomalies suggest an underlying genetic predisposition to TGCT, but traditional linkage studies have yet to identify a highly penetrant TGCT cancer susceptibility gene. In this paper, we investigate the familial occurrence of testicular and ovarian germ cell tumors. Methods We report a family in which a TGCT and an ovarian germ cell tumor (OGCT) occurred in two siblings, summarize the existing literature on familial occurrences of OGCT, either alone or in combination with extragonadal or TGCTs, and compare the incidence of familial and sporadic testicular and ovarian GCTs. Sporadic GCT data were obtained from the US Surveillance Epidemiology and End Results (SEER) registry. Results We identified 16 reports of OGCT occurring in conjunction with either ovarian, testicular or extragonadal GCT. In these familial cases, the mean age at onset of female dysgerminoma was younger than that noted in the general population (age 17 vs. age 24, p = 0.01). In SEER, the incidence of TGCT was 15 times higher than that of OGCT. Histologic distributions in males and females showed distinctly different patterns. Discussion Although the incidence of OGCTs in the general population is quite low, its occurrence in multiple members of the same family and in families with TGCT suggests that a gene conferring susceptibility to GCTs may exist in some families.     

Dermal cylindroma. Expression of intermediate filaments, epithelial and neuroectodermal antigens.

We report on immunohistochemical staining patterns in so-called apocrine tumors of skin with special emphasis on the dermal cylindroma. The results were compared with apocrine tubular adenoma, syringocystadenoma papilliferum and the normal eccrine sweat gland. A relationship of dermal cylindroma to the apocrine gland is suggested by expression of lysozyme and alpha 1-antichymotrypsin. The tumor shares keratin, epithelial membrane antigen (EMA) and EGF-receptor expression with eccrine and apocrine glands. The presence of intermingled cells with a coexpression of keratin and vimentin argues for a partial myoepithelia-like differentiation. Neuroectodermal antigens are missing. Therefore, dermal cylindroma is classified as an adnexal tumor of skin with a variable rate of cells of apocrine secretory, myoepithelial and undifferentiated phenotypes.     

Expression of testicular fatty acid-binding protein PERF 15 during germ cell apoptosis

PERF 15 is a testicular germ cell specific fatty acid-binding protein (FABP) isolated from rat. Indirect immunofluorescent analysis of juvenile rat testis showed that there were some strongly PERF 15-positive spermatocytes. These cells showed unclear nuclear structure and were predicted to undergo apoptosis. Apoptosis in germ cells is an important regulatory event to limit the number of germ cells in the seminiferous epithelium, but the physiological significance and molecular mechanisms of this testicular germ cell apoptosis are poorly understood. To determine whether PERF 15 participates in germ cell apoptosis, juvenile rat testis was examined by immunohistochemical and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) methods. Strongly PERF 15-positive cells and TUNEL-positive cells were co-localized in adjacent sections. Exposure to methoxyacetic acid (MAA), known to induce apoptosis in spermatocytes, increased the number of strongly PERF 15-positive cells in 25-day-old rats' testes. Therefore, it seems that PERF 15 is involved in both spermatogenesis and testicular germ cell apoptosis.     

Intermediate filament protein profiles of human testicular non-seminomatous germ cell tumors: correlation of cytokeratin synthesis to cell differentiation

The patterns of cytoskeletal differentiation were studied in 20 testicular non-seminomatous germ cell tumors by immunohistochemistry, using diverse monoclonal antibodies specific for different intermediate filament (IF) proteins and for desmoplakin. Immunofluorescence and immunoperoxidase methods on both formalin-fixed and frozen tissues were applied, in some cases together with a gel electrophoretic analysis of IF proteins. The tumors examined included embryonal carcinoma (EC), endodermal sinus tumor (EST), choriocarcinoma and teratoma. Nine of the tumors were composed of only one histological type, the others showed mixed components. Cytokeratins 8 and 18 were identified in all these neoplasms, but their immunostaining was weak in ECs. Cytokeratin 19 was absent or very scarce in ECs, but strongly expressed in ESTs, choriocarcinomas and teratomas, thus allowing the identification of small EST and choriocarcinoma elements in ECs even when they were morphologically not obvious. Occasionally, some cells in ECs and ESTs also stained for cytokeratins 4 and/or 17, indicating potential for epithelial stratification. The majority of the germ cell tumors showed varied amounts of vimentin, often in co-existence with cytokeratins. Neurofilaments were demonstrated in scattered tumor cells in a single case of EST. In the teratomas studied, each type of tissue component present showed the expected IF protein. However, in many germ cell tumors some stromal cells and blood vessels contained, in addition to vimentin and desmin, also cytokeratins 8 and 18. This heterogeneity of the cytoskeletal profile of germ cell tumors is indicative of the varied differentiation potential inherent in these neoplasms.(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic variants in the 8q24 locus and risk of testicular germ cell tumors

Much evidence supports the premise that population genetic variation contributes significantly to the risk of testicular germ-cell tumor (TGCT). However, investigations of the association between genomic markers and TGCT susceptibility are scarce. Single nucleotide polymorphisms (SNPs) at the locus 8q24 have recently been found to be associated with prostate, colorectal and breast cancer. The US Servicemen’s testicular tumor environmental and endocrine determinants (STEED) study was used to investigate the association of 15 specific 8q24 SNPs with TGCT and its two main histologic groups of seminoma and nonseminoma. Conditional and unconditional logistic regression models, adjusted for the matching variables of year of birth, race/ethnicity and serum date, were utilized to produce odds ratios (OR) and 95% confidence intervals (95%CI). The analysis included 680 controls and 568 TGCT cases. In the TGCT analysis, no SNP was associated with risk in both heterozygotes and variant homozygotes. When stratified by histology the seminoma analysis also showed no association with the 8q24 SNPs. Conversely, the analysis of nonseminomas had three tentative associations (rs6470494, OR_{genotype AG} = 1.15, 95%CI: 0.86–1.54; OR_{genotype GG} = 1.68, 95%CI: 1.04–2.73; p for trend = 0.04) (rs13254738, OR_{genotype GT} = 1.04, 95%CI: 0.77–1.40; OR_{genotype TT} = 1.62, 95%CI: 1.06–2.49; p for trend = 0.07) (rs10505476, OR_{genotype CT} = 0.67, 95%CI: 0.50, 0.91; OR_{genotype TT} = 0.81, 95%CI: 0.47–1.39; p for trend = 0.04). There was no linkage disequilibrium between any of the 8q24 SNPs analyzed in this population. In conclusion, this study has found little evidence for an association between the reported 8q24 SNPs and TGCTs, although the findings for nonseminoma may be worth further investigation.     

Comparative embryogenesis of Mecoptera and Lepidoptera with special reference to the abdominal prolegs

The eruciform larvae of holometabolous insects are primarily characterized by bearing a varying number of abdominal prolegs in addition to three pairs of thoracic legs. However, whether the prolegs are evolutionarily homologous among different insect orders is still a disputable issue. We examined the embryonic features and histological structure of the prolegs of the scorpionfly Panorpa byersi Hua and Huang (Mecoptera: Panorpidae) and the Oriental armyworm Mythimna separata (Walker) (Lepidoptera: Noctuidae) to investigate whether the prolegs are homologous between these two holometabolous insect orders. In the scorpionfly, paired lateral process primordia arise on abdominal segments I–VIII (A1–A8) in line with the thoracic legs in early embryonic stages, but degenerate into triangular protuberances in later stages, and paired medial processes appear along the midventral line before dorsal closure and eventually develop into unjointed, cone‐shaped prolegs. Histological observation showed that the lumina of the prolegs are not continuous with the hemocoel, differing distinctly from that of the basic appendicular plan of thoracic legs. These results suggest that the prolegs are likely secondary outgrowths in Mecoptera. In the armyworm, lateral process primordia appear on A1–A10 in alignment with the thoracic legs in the early embryonic stages, although only the rudiments on A3–A6 and A10 develop into segmented prolegs with the lumina continuous with the hemocoel and others degenerate eventually, suggesting that the prolegs are true segmental appendages serially homologous with the thoracic legs in Lepidoptera. Therefore, we conclude that the larval prolegs are likely not evolutionarily homologous between Mecoptera and Lepidoptera. J. Morphol. 277:585–593, 2016. © 2016 Wiley Periodicals, Inc.     

Expression of the HST1 oncogene in human germ cell tumors

HST1 (or HSTF1 in human gene nomenclature) is a transforming gene isolated from several cancerous and noncancerous cells. The HST1 protein is a heparin-binding growth factor with significant homology with human fibroblast growth factors and the mouse Int-2 protein. Here, we report the identification of expression of HST1 in a human teratoma cell line and in 5 out of 9 surgically resected human testicular germ cell tumors including seminomas and embryonal carcinomas. Mouse HST1 homologue was expressed in a certain stage of mouse embryo but not in postnatal mice.     

Contribution of intermediate filaments to cell stiffness, stiffening, and growth

It has been shown previously thatintermediate filament (IF) gels in vitro exhibit stiffening athigh-applied stress, and it was suggested that this stiffening propertyof IFs might be important for maintaining cell integrity at largedeformations (Janmey PA, Evtenever V, Traub P, and Schliwa M, JCell Biol 113: 155-160, 1991). In this study, the contribution ofIFs to cell mechanical behavior was investigated by measuring cellstiffness in response to applied stress in adherent wild-type andvimentin-deficient fibroblasts using magnetic twisting cytometry. Itwas found that vimentin-deficient cells were less stiff andexhibited less stiffening than wild-type cells, except at the lowestapplied stress (10 dyn/cm²) where the difference in thestiffness was not significant. Similar results were obtained frommeasurements on wild-type fibroblasts and endothelial cells aftervimentin IFs were disrupted by acrylamide. If, however, cells wereplated over an extended period of time (16 h), they exhibited asignificantly greater stiffness before than after acrylamide, even atthe lowest applied stress. A possible reason could be that theinitially slack IFs became fully extended due to a high degree of cellspreading and thus contributed to the transmission of mechanical stressacross the cell. Taken together, these findings were consistent withthe notion that IFs play important roles in the mechanical propertiesof the cell during large deformation. The experimental data also showedthat depleting or disrupting IFs reduced, but did not entirely abolish,cell stiffening. This residual stiffening might be attributed to theeffect of geometrical realignment of cytoskeletal filaments in thedirection of applied load. It was also found that vimentin-deficientcells exhibited a slower rate of proliferation and DNA synthesis thanwild-type cells. This could be a direct consequence of the absence ofthe intracellular IFs that may be necessary for efficient mediation ofmechanical signals within the cell. Taken together, results of thisstudy suggest that IFs play important roles in the mechanical properties of cells and in cell growth.

     

Retroperitoneal and metachronous testicular germ cell tumors with different histology and teratoma growing syndrome--a case report

It is presented a case of a 32-year-old male with the three primary tumors diagnosed within a time period of 3 years; retroperitoneal nonseminoma in 2002, retroperitoneal mature teratoma in 2004, and metachronous testicular seminoma in 2005. We discuss the unusual presentation of these three rare events occurring in the same patient without known risk factors.