Androgen receptor in laryngeal carcinoma: could there be an androgen-refractory tumor?

Androgen receptors (ARs) which are implicated in the pathogenesis of several malignancies can also be a possible downstream effector in laryngeal cancer. In the present study, 97 invasive squamous laryngeal carcinomas were studied by immunohistochemistry for protein expression of AR. Androgen receptors were expressed in 52.6% of tumor specimens, suggesting their implication in the pathogenesis of this tumor. Our study's aim was to investigate the hypothetical scenario of an androgen refractory laryngeal carcinoma where androgen receptors can be activated by nodal molecules in the course of an Epithelial-to-mesenchymal transition (EMT) phenomenon. In line with this we correlated AR expression with the expression of ILK, p-Akt, E-cadherin, β-catenin in our sample as well as with tumor grade and TNM stage. A reverse correlation between nuclear AR and cytoplasmic ILK expression was evidenced, indicating an interaction of those molecules in laryngeal carcinoma. Finally in our material, in those carcinomas that were expressing ARs, stronger nuclear expression of the receptor was characterized by poorer cell differentiation and correlated with the acquisition of EMT features like E-cadherin loss and β-catenin translocation raising a question whether activated ARs can drive an EMT procedure.

Survivin overexpression in HCC and liver cirrhosis differentially correlates with p-STAT3 and E-cadherin

Survivin, a member of the family of inhibitor of apoptosis proteins, functions as a key regulator of apoptosis and cell proliferation. Overexpression of survivin has been implicated in several human cancers, including human hepatocellular carcinoma (HCC). Although several factors have been shown in vitro to upregulate survivin expression in cancer cells, the in vivo regulators of survivin in human hepato-carcinogenesis are largely unknown. We studied by immunohistochemistry the protein expression of survivin in relation to cyclin D1, phosphorylated signal transducer and activator of transcription 3 (p-STAT3), beta-catenin, E-cadherin and phosphorylated-Akt (p-Akt) in 69 cases of HCC and adjacent liver cirrhosis. Survivin was expressed in 63/69 (91.3%) cases of HCC and in 40/47 (85.1%) cases of liver cirrhosis. Survivin localization in HCC was exclusively nuclear, while intense cytoplasmic and low nuclear expression of survivin was observed in cases of cirrhosis. Survivin expression in HCC correlated significantly with low grade tumors, expression of cyclin D1 and p-STAT3. Expression of survivin in liver cirrhosis correlated with downregulation of E-cadherin expression. There was no significant correlation of survivin with beta-catenin or p-Akt in HCC or liver cirrhosis. In conclusion, we showed an association of nuclear survivin with well differentiated HCC, as well as with the expression of the cell cycle regulator cyclin D1. Activation of STAT3 and loss of E-cadherin but not beta-catenin or Akt pathways seem to be implicated in survivin upregulation in HCC and liver cirrhosis.

Immunohistochemical detection of phosphorylated JAK-2 and STAT-5 proteins and correlation with erythropoietin receptor (EpoR) expression status in human brain tumors

Phosphorylated (activated) forms of Janus Kinase 2 (pJAK-2) and STAT-5 transcription factor (pSTAT-5), which are preferentially expressed after binding of erythropoietin (Epo) to its receptor EpoR, are known to be implicated in the molecular mechanisms controlling brain development. The purpose of this study was to investigate the expression of these proteins (pJAK-2, pSTAT-5, and EpoR) in human brain tumors compared with normal brain. Using specific antibodies and immunohistochemistry on formalin-fixed, paraffin-embedded semi-serial tissue sections a total of 87 human brain tumors and samples from normal brain tissue were studied. pJAK-2/pSTAT-5 nuclear co-expression was detected in 39% of astrocytomas, 43% of oligodendrogliomas, 50% of ependymomas, and in all (100%) of the medulloblastomas examined. In contrast, most of the meningiomas showed weak or no immunoreactivity for pJAK-2/pSTAT-5 proteins. A significant percentage of tumors exhibited pSTAT-5 immunoreactivity, being pJAK-2 immunonegative. EpoR/pJAK-2/pSTAT-5 co-expression was detected in a small percentage of astrocytomas (18%) and ependymomas (33%). Oligodendrogliomas and medulloblastomas were EpoR immunonegative. Tumor vessels exhibited EpoR, pJAK-2, and pSTAT-5 immunoreactivity. In normal brain tissue, EpoR immunoreactivity was detected in neurons and vessels whereas pSTAT-5 and pJAK-2 immunoreactivity was limited to some neurons and a few glial cells, respectively. These results indicate the existence of ligand (other than Epo)-dependent or independent JAK-2 activation that leads to constitutive activation of STAT-5 in most human brain tumors. Given the oncogenic potential of the JAK/STAT pathway, detection of different pJAK-2 and pSTAT-5 expression profiles between groups of tumors may reflect differences in the biological behavior of the various human brain tumors.

Bone regulatory factors NFATc1 and Osterix in human calcific aortic valves

BACKGROUND

Emerging evidence suggests that calcific aortic valve stenosis constitutes an active process sharing common features with atherosclerosis and bone formation. To further support this hypothesis, we investigated the expression of bone regulatory factors in calcified aortic valves.

METHODS-RESULTS

Formalin-fixed, paraffin-embedded tissue samples of human aortic tricuspid valves (n=54) were used from patients undergoing valve replacement for calcific, non-rheumatic aortic stenosis. As controls, fourteen aortic tricuspid valves (n=14) were obtained at autopsy from patients without clinical and morphological aortic valve lesions. Sections from both stenotic and normal aortic valve leaflets were studied immunohistochemically. Interstitial cells in stenotic valves showed intense expression of Sox9, Runx2 and Osterix (Osx) whereas NFATc1 was expressed in interstitial and inflammatory cells. In addition, NFATc1 expression correlated significantly with Osx (r=0.458, p<0.001) and Runx2 (r=0.387, p<0.001). Finally, there was accumulation of activated interstitial cells, T lymphocytes and macrophages as well as intense neoangiogenesis in pathological leaflets.

CONCLUSIONS

The presence of NFATc1 and Osx in our material lends further support to the hypothesis that during the process of aortic valve calcification there is expression of osteoblastic phenotypes by valvular cells.

Estrogen receptor-beta expression in human laryngeal carcinoma: correlation with the expression of epithelial-mesenchymal transition specific biomarkers

Laryngeal carcinoma is a malignancy of the respiratory tract with a significantly higher male to female ratio, suggesting involvement of gender-depended factors in the pathogenesis. Estrogen influences the pathological processes of hormone-dependent cancers, such as breast, prostate and ovarian cancers, through its receptors, estrogen receptor-alpha (ER-alpha) and -beta (ER-beta). While ER-alpha promotes cell proliferation, recent studies indicate that ER-beta is protective against carcinoma progression into an invasive state. However, it is unclear whether ER-beta plays a role in laryngeal cancer. In the present study we examined the expression of ER-beta in 80 invasive human squamous laryngeal carcinomas by immunohistochemistry and correlated ER-beta expression with markers of epithelial-mesenchymal transition (EMT). ER-beta was expressed in 83% of tumour specimens where it was localized in the nuclei of tumour cells. The expression of ER-beta correlated positively with the maintenance of E-cadherin and beta-catenin at cell junctions and negatively with the loss of E-cadherin, nuclear translocation of beta-catenin and increased TNM stage. We concluded that estrogen receptor-beta expression is documented in laryngeal cancer indicating a possible role in the pathogenesis of this malignancy. It is suggested that ER-beta could protect tumour cells from acquiring aggressive EMT features such as E-cadherin downregulation and nuclear beta-catenin activation.

Loss of inhibitor of growth (ING-4) is implicated in the pathogenesis and progression of human astrocytomas

Inhibitor of growth 4 (ING-4) is a tumor suppressor gene that interacts with nuclear factor-kappaB (NF-kappaB) and represses its transcriptional activity. Several lines of evidence suggest that the tumor suppressor gene ING-4, the transcription factor NF-kappaB and its target genes matrix metalloproteases MMP-2, MMP-9 and urokinase plasminogen activator (u-PA) are critically involved in tumor invasion. The aim of the present study was to investigate immunohistochemically the expression pattern of ING-4, NF-kappaB and the NF-kappaB downstream targets MMP-2, MMP-9 and u-PA in human astrocytomas from 101 patients. We found that ING-4 expression was significantly decreased in astrocytomas, and ING-4 loss was associated with tumor grade progression. Expression of p65, a NF-kappaB subunit, was significantly higher in grade IV than in grade III and grade I/II tumors, and a statistical significant negative correlation between expression of ING-4 and expression of nuclear p65 was noticed. MMP-9, MMP-2 and u-PA were overexpressed in human astrocytomas. Of note, astrocytomas of advanced histologic grades (grade III, IV) displayed significantly higher expression levels of these proteins compared to tumors of lower grades (grade I, II). Collectively, our data suggest an essential role for ING-4 in human astrocytoma development and progression possibly through regulation of the NF-kappaB-dependent expression of genes involved in tumor invasion.

Overexpression of hedgehog pathway molecules and FOXM1 in non-small cell lung carcinomas

The hedgehog (HH)-signaling pathway is implicated in developmental processes and its aberrant activation in adult tissues has been associated with malignancy. The aim of this study was to determine the expression pattern of HH-signaling molecules in non-small cell lung carcinomas (NSCLC), as well as the involvement of the transcription factor FOXM1, that controls cell proliferation, in this process. Paraffin-embedded tissue sections of 80 NSCLC cases and adjacent non-neoplastic lung parenchyma were immunohistochemically analyzed with anti-SHH, anti-Patched1 (PTCH1), anti-Smoothened (SMO), anti-GLI1, anti-GLI2 and anti-FOXM1 antibodies. Correlations of HH molecules with clinicopathological parameters and FOXM1 expression were evaluated. All the HH-signaling molecules examined were overexpressed in NSCLC compared with the adjacent non-neoplastic lung parenchyma. HH pathway activity and expression of PTCH1 and SMO were significantly higher in squamous cell carcinomas compared to other NSCLC histological types. Activation of HH pathway and PTCH1 expression were correlated with tumor grade being higher in low grade tumors. There was a significant correlation of lymph node metastases with expression of SMO in all NSCLC histological types and with nuclear GLI1 immunolocalization only in adenocarcinomas. Overexpression of FOXM1 in NSCLC was also significantly correlated with PTCH1, SMO and GLI1 expression. In conclusion, HH-signaling pathway is activated in NSCLC and correlates with histological type, prognostic parameters of the tumors as well as with the increased expression of FOXM1.

ILK overexpression in human hepatocellular carcinoma and liver cirrhosis correlates with activation of Akt

Hepatocellular carcinoma (HCC) is one of the most common life-threatening malignancies in the world. The molecular mechanisms leading to the development of HCC are complex and only recently have they begun to be clarified. Integrin linked-kinase (ILK), a multifunctional signaling and scaffold protein of focal adhesion plaques, has been implicated in the pathogenesis of several human malignancies. In the current study the expression of ILK, beta-catenin and E-cadherin and the phosphorylation of Akt were studied by immunohistochemistry in 69 human HCCs and adjacent normal and cirrhotic liver parenchyma. ILK and phosphorylated-Akt (p-Akt) immunostaining was observed in 100 and 79.7% of HCCs, respectively, and their protein levels correlated significantly. Activation of beta-catenin and downregulation of E-cadherin were frequently observed in HCC, but they were not related to ILK expression. A strong correlation between ILK expression and phosphorylation of Akt was also observed in cirrhotic liver. Moreover, downregulation of E-cadherin and membranous beta-catenin were found in cirrhotic tissue suggesting their involvement in the liver tissue remodeling observed in cirrhosis. Our results indicate that ILK overexpression during liver oncogenesis and cirrhosis correlates with activation of Akt but not with other conventional ILK targets.

p75 and TrkC neurotrophin receptors demonstrate a different immunoreactivity profile in comparison to TrkA and TrkB receptors in human normal pituitary gland and adenomas

BACKGROUND/AIMS

Recent knowledge indicates that neurotrophins play a significant role in neuroendocrine systems through their specific receptors TrkA, TrkB, TrkC and low-affinity p75(NTR) receptor. TrkA and TrkB receptors have been previously detected in numerous endocrine cells in human anterior pituitary and adenomas. In the present study, the localization of p75(NTR) and TrkC along with TrkA and TrkB receptors was investigated.

METHODS

Semi-serial paraffin-embedded sections of 5 human normal pituitaries and 30 adenomas were immunostained using specific antibodies.

RESULTS

Expression of p75(NTR) receptor was demonstrated in the intricate capillary and reticulin network in the anterior pituitary and in the pericapillary tissue and pituicytes in the posterior lobe. p75(NTR) immunoreactivity was absent from all adenomas. In normal anterior pituitary, a few scattered cells showed weak TrkC immunoreactivity in contrast to a high percentage of endocrine cells distributed throughout the pars distalis and pars intermedia which exhibited strong TrkA and/or intermediate TrkB immunoreactivity. Double immunohistochemistry demonstrated TrkA immunoreactivity in more than 80% of lactotropes and 70% of corticotropes and to a lesser extent in other cell types. Furthermore, in the majority of adenomas, independently of type, sex and age, a high percentage of TrkA- and/or TrkB-positive cells was detected. Interestingly, TrkC expression appeared to be increased in some adenomas compared to normal pituitary. Endothelial cells and perivascular connective tissue were always TrkB-immunostained.

CONCLUSION

The above findings support a potential role of all neurotrophins, through their different receptors, in pituitary functions.

Prognostic significance of TGFbeta-1 and pSmad2/3 in breast cancer patients with T1-2,N0 tumours

BACKGROUND

The transforming growth factor beta (TGFbeta) signaling pathway has been shown to exert divergent effects and to cross-talk with estrogen pathways in mammary gland tumorigenesis. TGF signaling in early stage breast cancer was investigated by examining the expression of TGFbeta-1 and the signaling mediators pSmad2/3 and Smad4. Their association with oestrogen and progesterone receptors, as well as with clinical and pathological features was also analyzed.

PATIENTS AND METHODS

Sixty-one tumor specimens from surgically treated patients with primary T12,N0 breast cancer were examined. The expression of TGFbeta-1, pSmad2 and Smad4 was assessed implementing immunohistochemical assays.

RESULTS

TGFbeta-I, pSmad2/3 and Smad4 were expressed in 50.9%, 74.0% and 61.0% of specimens, respectively. The degree of expression of the three molecules was significantly associated with each other. Loss of pSmad2/3 expression indicated a shorter disease-free survival in all patients, including those with oestrogen receptor-positive tumors. Patients not expressing TGFbeta-1 were 4.6 times more likely to experience distant recurrence.

CONCLUSION

Our results demonstrate that pSmad2/3 and TGFP-1 may be promising novel prognostic markers for T1.2,N0 breast carcinomas.

Expression of p75NTR and Trk neurotrophin receptors in the enteric nervous system of human adults

Recent evidence suggests that the expression of p75NTR and Trk neurotrophin receptors is essential for neuronal survival, not only during development, but also in adulthood. The aim of the present study was to investigate the cell localization and distribution of p75NTR and Trk receptors in the normal adult human enteric nervous system (ENS) using double-label immunohistochemistry. Immunoreactivity for p75NTR was observed in a few neurons, whereas Trk immunoreactivity was present in a higher percentage of neurons. Strong expression of both types of neurotrophin receptors was found in the enteric glia. In addition, Trk immunoreactivity was localized to nerve endings in the lamina propria, muscularis mucosa and along or between circular and longitudinal smooth muscle layers, as well as to the enteric epithelium. Furthermore, polynuclear cells, mast cells and folliculoreticular cells in the germinal layer of lymph nodes displayed p75NTR and/or Trk immunopositivity. Expression of neurotrophin receptors in an inflammatory tissue sample was much more intense compared with that of normal tissue samples. These results suggest that neurotrophin receptors, through interactions with neurotrophins, may play a critical role in functional integrity of the ENS during adulthood.

ILK over-expression in human colon cancer progression correlates with activation of beta-catenin, down-regulation of E-cadherin and activation of the Akt-FKHR pathway

Integrin-linked kinase (ILK) has been implicated in the development and progression of several human malignancies. However, the role of ILK in human colon cancer progression is not well established, neither have its possible in vivo downstream effectors in the disease been identified. We studied, by immunohistochemistry, ILK, beta-catenin, E-cadherin, p-Akt and p-FKHR protein expression in 125 primary colon carcinomas and 45 corresponding lymph node metastases. ILK was expressed in 98.4% of the primary tumours and in 100% of metastatic lesions. The levels of ILK expression correlated strongly with tumour invasion, tumour grade and stage and were significantly higher in metastatic tumours. Activation of beta-catenin, down-regulation of E-cadherin and activation of the Akt-FKHR pathway correlated significantly with both ILK expression and tumour progression parameters. In conclusion, our results suggest that ILK may have an important role in progression of human colon cancer, possibly through in vivo regulation of beta-catenin, E-cadherin and Akt pathways. Our study also provides some evidence implicating p-FKHR in human colon carcinogenesis and ILK signalling.

Expression of the licensing factors, Cdt1 and Geminin, in human colon cancer

Licensing of chromatin for replication is an evolu-tionarily conserved step in the control of cell division and genomic integrity. Proteins that participate in licensing have been recently documented to denote the proliferative state of cells and they have been proposed as diagnostic and prognostic markers in human cancer. Cdt1 was recently discovered as an important licensing factor, that is inhibited by Geminin. In the present study we analyzed Cdt1 and Geminin expression in human colon cancer. We showed that Cdt1 protein is highly expressed in human neoplastic lesions of the colon while its cell-cycle phase-specific expression profile appears preserved during human carcinogenesis. Similarly, Geminin, Cdt1's inhibitor, is also overexpressed in colon carcinomas and its expression correlates with significant clinicopathological parameters of the disease. Moreover, both Cdt1 and Geminin expression are severely downregulated upon differentiation of Caco-2 cells, an in vitro model of intestinal epithelial differentiation.

Hsp27 Expression Coincides with Epidermal Stratification during Human Epidermal Morphogenesis

Heat shock protein 27 (Hsp27), apart from its protective function in response to stress, is implicated in the regulation of cell growth, differentiation and apoptosis. Data on the expression of Hsp27 in the developing human epidermis are sparse and partially conflicting. Thus, the purpose of the present study was to investigate Hsp27 expression during the morphogenesis of human epidermis. Skin biopsies and dispase-separated epidermal sheets obtained from 7 human embryos (7 and 8 weeks estimated gestational age, EGA), from 79 human fetuses (9-23 weeks EGA) and from 10 healthy adult volunteers were investigated by immunohistochemistry and Western blotting, respectively. The earliest detection of Hsp27 expression was found by immunohistochemistry at the 12th week EGA (basal and intermediate layer) and by Western blotting at the 9th week EGA. From the 16th to the 23rd week EGA immunoreactivity was not detectable in the basal layer, whereas in the overlying layers it revealed a differentiation-related pattern. The simultaneous onset of epidermal stratification and Hsp27 expression (9th week EGA) and the alterations of the latter in the subsequent stages of development, suggest that this stress protein may be involved in the molecular events underlying human epidermal morphogenesis.

Qualitative and quantitative alterations of cell surface carbohydrate residues during epidermal morphogenesis

The purpose of this study was to investigate the carbohydrate residue composition of cell surface in the developing epidermis and to define the chronological sequence of its alterations in human fetuses from the 10th to the 20th weeks of gestation and at the 23rd week of gestation, using a panel of six biotinylated lectins: Concanavalin A, Ulex europaeus agglutinin-I, Ricinus communis agglutinin-I, Peanut agglutinin, Wheat germ agglutinin, and Dolichos biflorus agglutinin. Distinct qualitative and quantitative alterations in the expression of cell surface carbohydrate residues were found during epidermal morphogenesis prior to keratinization (10th to 20th weeks). At the 23rd week of gestation, the already keratinized fetal human epidermis revealed a pattern of cell surface glycosylation very similar to that of the adult human epidermis. Further studies are now warranted to answer the question regarding whether the glycosylation pattern in the developing human epidermis is disturbed in fetuses with genodermatoses and whether these disturbances might be important for prenatally diagnosing the latter.

AP-1 and heat shock protein 27 expression in human astrocytomas

PURPOSE

In previous work we have shown that the expression of heat shock protein 27 (Hsp27) is associated with anaplastic potential of astrocytomas (Anticancer Res 1997, 17:2677-2682). Heat shock protein-coding genes have been found to have a putative AP-1 (activator protein-1)-binding site in their promoter region and the synthesis of these proteins is induced by the same extracellular stimuli that also activate AP-1 (a homo/heterodimer of members of the Jun and Fos families). In order to detect the putative relation of Hsp27 with AP-1 activation in human astrocytomas we examined eighty astrocytic tumors with different grades of malignancy for c-Jun, c-Fos, and Hsp27 expression.

METHODS

Six pilocytic astrocytomas (WHO grade I), 15 diffuse fibrillary astrocytomas (WHO grade II), 19 anaplastic astrocytomas (WHO grade III), and 40 glioblastomas multiforme (WHO grade IV), were studied by immunohistochemistry using monoclonal and polyclonal antibodies directed against human Hsp27, c-Fos, and active (phosphorylated) forms of c-Jun (p-c-Jun). Monoclonal antibodies against the phosphorylated forms of the over-expressed MAP kinases JNK (c-Jun N-terminal kinase) (p-JNK) and p38 (p-p38) were also used.

RESULTS

Overexpression of p-c-Jun, c-Fos and p-JNK was observed in the majority of glioblastomas (grade IV) whereas only minimal expression was noted in diffuse fibrillary astrocytomas (grade II). Hsp27 expression was observed only in the tumor specimens where c-Jun and c-Fos were co-expressed. AP-1/Hsp27 co-expression was associated with ascending grading of malignancy and it was independent of the proliferation index of the tumors.

CONCLUSIONS

Our findings suggest that during malignant progression of astrocytomas there is activation of signal transduction cascade(s) culminating in AP-1 induction.

Lectin-binding pattern of primary malignant melanomas and melanocytic nevi

A panel of six biotinylated lectins was applied in order to study the composition and distribution of plasma membrane carbohydrate residues in 83 primary cutaneous melanomas (MMs) and in 85 melanocytic nevi (MN) with the avidin-biotin peroxidase technique. No clear-cut differences between MN and MMs were observed with regard to the staining with lectins. In MN and MMs derived from different patients, the lectin-binding pattern was variable and heterogeneous even within the individual nevi or melanomas. It seems reasonable, therefore, to assume that the lectin-binding pattern cannot be regarded as a reliable histochemical marker for the differentiation of MN from MMs. Moreover, because the pattern reveals no statistically significant correlation with the thickness or the depth of invasion of MM, it seems to lack prognostic significance.

Does sex steroid receptor status have any prognostic or predictive significance in brain astrocytic tumors?

Formalin-fixed paraffin-embedded tumor specimens from 90 patients with supratentorial astrocytic brain tumors were immunostained following microwave pretreatment using monoclonal antibodies against estrogen receptor (ER), progesterone receptor (PgR), and PS2 protein (PS2) and the streptavidin/peroxidase method. The immunohistochemical analysis was scored in a semiquantitative fashion incorporating both the intensity and distribution of specific staining (SCORE) and the immunohistochemical results were correlated with histologic grade of tumors and patient's sex and age. Strong PgR nuclear immunopositivity was observed in 27 of 46 (59%) glioblastomas, in 9 of 20 (45%) anaplastic astrocytomas, and in 2 of 24 (8%) astrocytomas. The mean PgR score was 18.5 in glioblastomas, 11.3 in anaplastic astrocytomas, and 0.9 in astrocytomas. The expression of PgR immunoreactivity appeared to be dependent on the age and independent of the sex of patients. All tumors were negative for ER and PS2 protein. Normal astrocytes remained consistently negative for both sex steroid receptors and PS2. Our findings indicate a consistent expression of PgR in a number of poorly differentiated tumors including glioblastomas and anaplastic astrocytomas contrasting with the low PgR score values found in benign astrocytomas. The absence of ER and PS2 immunoreactivities supports the hypothesis that estrogen receptor in astrocytic tumors is probably truncated. However, regional tumor heterogeneity may be a limiting factor for the use of ER, PgR, PS2 immunohistochemistry in the evaluation of routine pathology specimens examination.

Induction of peripheral neuroblastomas in Syrian hamsters after injection as neonates with JC virus, a human polyoma virus

Neuroblastomas developed in 10 of 31 Syrian hamsters inoculated intraocularly with JC virus, a human polyoma virus. The latent period was 6 to 11 months. Primary tumors occurred in the abdominal cavity, pelvis, mediastinum, and neck region. The origin of one tumor from the adrenal gland was demonstrated. Metastases were seen in the liver, bone marrow, and lymph nodes. Two neuroblastomas arising in this experiment were transplanted serially in weanling hamsters, and a tissue culture cell line was established from one of the transplanted tumors. T-antigen was detected in three of five primary tumors tested and in the transplanted tumors. Antibody against T-antigen was demonstrated in sera from five of six animals with neuroblastomas. Neuroblastomas also developed after combined s.c. and i.p. injection of JC virus.

Generalized gangliosidosis type II (juvenile GM1 gangliosidosis). A pathological, histochemical and ultrastructural study

Pathological, histochemical and ultrastructural studies on 3 siblings with GM1 gangliosidosis type II are reported. These studies support a biochemical defect with profound deficiency of beta-galactosidases which results in widespread accumulation of the GM1 ganglioside and its asialo derivative in brain and to a lesser extent in viscera, as well as in storage of a keratan sulphate-like mucopolysaccharide. Striking valvular changes in the heart without myocardial involvement were seen in all cases. The histochemical and ultrastructural changes are similar to those seen in GM1 gangliosidosis type I, though less severe. Autosomal recessive inheritance without apparent ethnic predilection seems likely.