Wilms tumor 1 mutations in the pathogenesis of acute myeloid leukemia.

Wilms tumor 1 (WT1) has long been implicated in acute myeloid leukemia. It has been described to be both overexpressed and mutated in different forms of acute myeloid leukemia, and overexpression has been reported to play a prognostic role in this disease. However, the precise mechanism through which WT1 may play a role in leukemogenesis has remained elusive. In recent years, new evidence has emerged that points towards a novel role of WT1 mutations in the deregulation of epigenetic programs in leukemic cells through its interaction with TET proteins. Herein we review the current status of the field and its therapeutic and prognostic implications in acute myeloid leukemia.

p53 Immunohistochemistry expression in Wilms tumor: a prognostic tool in the detection of tumor aggressiveness.

PURPOSE: We studied whether immunohistochemical expression of p53 in Wilms tumors correlates with tumor aggressiveness. We also examined whether preoperative chemotherapy results in any alteration of p53 expression. MATERIALS AND METHODS: A total of 18 patients underwent preoperative chemotherapy and 30 underwent immediate surgery for Wilms tumor. All children were younger than 10 years and had histologically confirmed disease. Patients with a bilateral tumor or a syndrome related to Wilms tumor were excluded. All pathology slides were uniformly stained for p53 protein, and p53 staining density and intensity were scored. The p53 scoring was then compared to the clinical behavior of the Wilms tumor, ie unfavorable tumor staging, and survival and recurrence rates. RESULTS: In the direct surgery and the preoperatively treated groups p53 positivity correlated with unfavorable Wilms tumor staging (p = 0.007). In addition, a positive p53 correlation predicted poorer survival (p = 0.017). Interestingly patients who underwent preoperative chemotherapy had an increased intensity of p53 staining compared to the direct surgery group (p <0.001). CONCLUSIONS: This study provides preliminary evidence that a higher score for immunohistochemical p53 expression correlates with unfavorable Wilms tumor staging and predicts poorer survival. This test could become a useful addition to the current histopathological analysis of Wilms tumor.

B7-h1 as a biomarker for therapy failure in patients with favorable histology Wilms tumor.

PURPOSE: A minority of children with Wilms tumor will experience tumor recurrence. In a previous pilot study we found an association between expression of an immune costimulatory molecule, B7-H1, and tumor recurrence in favorable histology Wilms tumor. We sought to verify the prognostic value of B7-H1 as a biomarker in favorable histology Wilms tumor. MATERIALS AND METHODS: We performed a nested case-control study of tumors from the Fifth National Wilms Tumor Study. We randomly selected 44 children unsuccessfully treated (cases) and 49 who were successfully treated for favorable histology Wilms tumor (controls). Cases and controls were matched based on tumor stage, and the analysis was restricted to children who underwent initial resection. We excluded patients with stage IV or V disease and those treated with chemotherapy or radiation. Tumor specimens were stained for B7-H1 expression. RESULTS: Of the 93 total samples analyzed 60 (65%) demonstrated B7-H1 staining, with staining diffusely present in 13 (22%) and blastema predominant in 34 (57%). B7-H1 expression was associated with failure of initial therapy (p = 0.006). Patients with tumors showing less than 20% B7-H1 positive cells were at lower risk for treatment failure, while those with tumors exhibiting greater than 60% B7-H1 positive cells were at greater risk for treatment failure. This association appeared to be independent of tumor stage. CONCLUSIONS: B7-H1 expression by favorable histology Wilms tumor is associated with an increased risk of failure of initial therapy.

Differential expression of STAT1 and IFN-γ in primary and invasive or metastatic wilms tumors.

BACKGROUND AND OBJECTIVES: IFN/STAT1 signaling has been found to be not only associated with an aggressive tumor phenotype but also activated and functional during metanephric development. This study was undertaken to evaluate STAT1 and IFN-γ expression and its relation to histopathological features of primary and invasive/metastatic Wilms tumors. METHODS: Immunohistochemistry was used to determine the expression and cellular distribution of STAT1 and IFN-γ in 18 pairs of primary and corresponding invasive/metastatic Wilms tumors and 40 primary tumors without invasion or metastasis. RESULTS: Positive rate of STAT1/IFN-γ expression was 66.7%/61.1% and 72.2%/77.8% in 18 pairs of primary and associated invasive/metastatic Wilms tumor tissues, while 35.0%/27.5% in 40 primary tumors without invasion or metastasis. The expression of STAT1 and IFN-γ was significantly associated with invasion/metastasis (P = 0.025; P = 0.015). There was a positive correlation between STAT1 and IFN-γ expression in all Wilms tumor tissues (χ(2) = 23.408, P = 0.05, r = 0.555). The expression of STAT1 and IFN-γ between primary and matched invasive/metastatic tissues was concordance, respectively (P = 0.710 and P = 0.375). CONCLUSIONS: These results suggest that IFN-γ/STAT1 signaling might have clinical potential as a promising predictor to identify individuals with poor prognostic potential and as a possible novel target molecule of therapy for Wilms tumor.

Prognostic value of survivin expression in Wilms tumor.

PURPOSE: To determine survivin expression patterns in Wilms tumor (WT) and compare it with the expression in normal renal tissue. Also, to analyse cytoplasmic and nuclear survivin expression in relation to histological type, prognostic group and tumor stage. METHODS: Immunohistochemical expression of survivin was analysed in 59 cases of primary WT and in 10 normal kidney specimens, taken from the same patients, but distant from the tumor. RESULTS: 51 out of 59 cases of WT (86.44%) showed decreased cytoplasmic survivin expression and 4 out of 59 cases of WT (6.78%) showed nuclear overexpression of survivin. There was statistically significant difference in the frequency of decreased cytoplasmic expression of survivin in individual components of WT (p=0.005). Decreased cytoplasmic expression of survivin in epithelial, blastemal and stromal component was found significantly more often in low stage WT compared to high stage WT (Fisher exact test, p=0.0002, p=0.002, p=0.002, respectively). There was no statistically significant difference in the frequency of survivin nuclear overexpression between different stages of WT (Fisher exact test, p=0.564), histological types (Fisher exact test, p=0.915), or between different prognostic groups (Fisher exact test, p=1). CONCLUSION: Decreased survivin cytoplasmic expression or nuclear overexpression may be related to favorable prognosis of WT.

Transmission Electron Microscopy: A Surgical Pathology Tool for Neuroblastoma.

Pediatric small round blue cell tumors (PSRBCT) are an intriguing and challenging collection of neoplasms. Light microscopy of small round blue cell tumors identifies small round cells. They harbor a generally hyperchromatic nucleus and relatively scanty basophilic cytoplasm. Pediatric small round blue cell tumors include several entities. Usually, they incorporate Wilms tumor, neuroblastoma, rhabdomyosarcoma, Ewing sarcoma, retinoblastoma, lymphoma, and small cell osteosarcoma, among others. Even using immunohistochemistry, the differential diagnosis of these neoplasms may be controversial at light microscopy. A faint staining or an ambiguous background can deter pathologists from making the proper diagnostic decision. In addition, molecular biology may provide an overwhelming amount of data challenging to distinguish them, and some translocations may be seen in more than one category. Thus, transmission electron microscopy (TEM) can be extremely valuable. Here we emphasize the modern protocol for TEM data of the neuroblastoma. Tumor cells with tangles of cytoplasmic processes containing neurosecretory granules can diagnose neuroblastoma.

Cytoplasmic p63 immunohistochemistry is a useful marker for muscle differentiation: an immunohistochemical and immunoelectron microscopic study.

TP63, a member of the TP53 gene family, is a nuclear marker of myoepithelial cells. Antibody against p63 is frequently used to aid in the diagnosis of prostate carcinoma, as well as in the identification of myoepithelial cells in other tissues including the breast. p63 is also a marker for squamous cell carcinoma. Recently, it was found that all p53 family members are involved in regulating the process of muscle differentiation through the retinoblastoma (RB) protein. Ablation of these p53 family functions blocks the differentiation program and promotes malignant transformation by enabling cooperating oncogenes to transform myoblasts. We therefore studied p63 expression in a number of neoplasms with myogenic differentiation. Immunohistochemical staining for p63 was performed on paraffin sections from 38 rhabdomyosarcomas, five leiomyomas, five leiomyosarcomas, five rhabdomyomas, five rhabdomyomatous Wilms tumors, three normal cardiac muscles, one medullomyoblastoma, one pleuropulmonary blastoma with rhabdomyomatous differentiation, and one teratoma with prominent rhabdomyoblasts. Each case was also stained with desmin. Unlike the nuclear staining scored in myoepithelial cells, only cytoplasmic staining for p63 was considered positive. Of 38 cases of rhabdomyosarcoma, 36 showed cytoplasmic p63 staining; 24 of these showed highlighting of cross-striations superior to that of desmin. In addition, 5/5 rhabdomyomas, 5/5 rhabdomyomatous Wilms tumors, 1/1 pleuropulmonary blastoma with rhabdomyomatous differentiation, 1/1 teratoma with atypical rhabdoblasts, and 1/1 medullomyoblastoma exhibited cytoplasmic p63 staining. Normal cardiac muscle samples (3/3) also demonstrated positive cytoplasmic staining and distinct cross-striations. Smooth muscle tumors exhibited only very focal and faint cytoplasmic staining in 5/5 leiomyomas and 4/5 leiomyosarcomas. Immunoelectron microscopic study of skeletal muscle showed p63 localization to the Z bands of sarcomeres. We conclude that p63 immunostain is a sensitive marker for skeletal muscle differentiation and highlights the cross-striations of strap cells with exceptional definition.

Analysis of multiple growth regulatory proteins using dissociable staining antibody arrays on solid tumor biopsy specimens.

Growth of tumor cells is often a function of deregulated growth factor receptors and their corresponding intracellular signalling molecules. The dissociable antibody staining arrays have the versatility to rapidly identify the expression, activation, and localization of such molecules and pathways in biopsy specimens. This report describes a protocol to quantify the activity of a panel of signalling molecules in Wilms tumor biopsy specimens and surrounding nonmalignant renal cells. We propose that this technique can be used to rapidly identify multiple markers and may aid in the study of aberrant growth regulatory mechanisms and potential targets for therapeutics from pathologic specimens.

Increased tissue factor expression and poor nephroblastoma prognosis.

PURPOSE: There is potential interaction between malignant cell growth and the coagulation pathway. Recent studies suggest that tissue factor, a primary initiator of the extrinsic coagulation pathway, is expressed in various solid tumors in association with increased angiogenesis. To our knowledge we report for the first time the detection of tissue factor expression by immunohistochemistry in Wilms tumors and its correlation with clinical outcomes. MATERIAL AND METHODS: Tissue factor expression detected by immunohistochemistry was assessed in 41 formalin fixed, paraffin embedded Wilms tumor cases treated at university hospitals. We correlated findings with tumor recurrence and cancer specific survival. RESULTS: Positive immunohistochemistry detection of tissue factor was observed in 88.3% of the tumors analyzed. Tissue factor on immunohistochemistry was associated with tumor recurrence and survival (p = 0.01 and 0.02, respectively). Increased immunohistochemical detection of tissue factor was the most important risk factor for recurrence and mortality in our population on bivariate and multivariate analysis. CONCLUSIONS: Tissue factor is a promising research subject as a prognostic factor for Wilms tumor. More studies are needed to clarify the mechanisms by which tissue factor affects cancer progression and outcome, and its potential role as a therapeutic target.

Role of DNA content analysis and immunohistochemistry in the evaluation of the risk of unfavourable outcome in Wilms' tumours.

BACKGROUND: Wilms' tumour (WT) is the most common solid tumour affecting young children. Its histological diversity leads to difficulties in predicting the outcome. MATERIALS AND METHODS: Image analysis cytometry and immunohistochemistry with a selected panel of antibodies were performed in 23 cases of WT considered of intermediate risk according to the revised International Society of Pediatric Oncology (SIOP) working classification of renal tumours of childhood. In this series, a tumour was considered aggressive according to its propensity for metastases or its recurrence. RESULTS: Out of the 14 non-aggressive WT, 4 were found to be diploid and 10 were aneuploid including 6 that were heterogeneous for DNA-ploidy. All the tumours presented a low proliferative index and were negative for p53 and p57(kip2) immunostaining. Out of the 9 aggressive tumours, all were aneuploid and 4 were found to be heterogeneous for DNA-ploidy. They all presented a high degree of cell proliferation and 7 were positive for p53 immunostaining. Only two were positive for the p57(kip2) marker. The only fatal case revealed an aneuploid-homogeneous DNA-ploidy analysis, was p53 and p57(kip2) positive and presented a high cell proliferation index. CONCLUSION: A significant correlation between the presence of focal DNA-aneuploidy in Wilms' tumours and adverse prognosis is not established, but some immunohistochemical markers may be useful for the clinical evaluation of these tumours and to help in predicting the risk of an unfavourable outcome.

S100 protein expression distinguishes metanephric adenomas from other renal neoplasms.

Metanephric adenoma is a benign renal neoplasm with morphologic features similar to those of malignant renal neoplasms, such as papillary renal cell carcinoma (RCC) and Wilms' tumor. Different methods have been used to distinguish between metanephric adenoma and papillary RCC and Wilms' tumor. However, some techniques are not always available, such as certain immunohistochemical stains, cytogenetics, molecular genetics, and electron microscopy. In the current study, we compared the expression of S100 protein in 15 cases of metanephric adenoma, 10 cases of Wilms' tumor, and 13 cases of papillary RCC. Our results revealed strong expression of S100 proteins in all cases of metanephric adenoma, weak expression in two cases of Wilms' tumor, and no expression in any of the cases of papillary RCC. These findings indicate that S100 could be a useful and accessible tool for the diagnosis of metanephric adenoma.

Difficulties in diagnosing small round cell tumours of childhood from fine needle aspiration cytology samples.

There are four basic reasons for the difficulties in diagnosing small round cell tumours (SRCT) in childhood from fine needle aspiration cytology (FNAC) samples. First, SRCTs are rare and it is difficult for cytopathologists to obtain enough experience for rendering reliable diagnoses. Second, SRCTs are morphologically very similar. Third, many SRCTs do not have specific antigens which could be demonstrated with immunocytochemistry (ICC) or they lose them when poorly differentiated. In addition, cross reactivity exists between some SRCTs. Unstandardized performance of ICC also contributes to the difficulties due to unreliable results. Fourth, suboptimal FNAC samples add additional pitfalls. The latter may be due to partly degenerate samples or to unrepresentative ones in cases where a SRCT is a heterologous component of another nosological entity. Lymphoma, neuroblastoma, nephroblastoma, Ewing's tumour/primitive neuroendocrine tumours and rhabdomyosarcoma are discussed in detail, while other less common SRCTs are mentioned as differential diagnoses when appropriate. The use of cytogenetic and molecular techniques for differentiating between certain SRCTs is helpful in some doubtful cases. However, there are still problems in the use of these techniques, especially their cost which may delay their being introduced in every cytopathology laboratory.

Clear cell sarcoma, cellular mesoblastic nephroma and metanephric adenoma: cytological features and differential diagnosis with Wilms tumour.

Wilms' Tumour (WT) is the most common kidney tumour in childhood, this fact and the embryonic complexity of WT create, whenever one of its three classical components predominates in cytologic smears, difficulties in the differential diagnoses with other less common entities. In the present study, we review the cytological and immunohistochemical characteristics of three children renal tumours, a Clear Cell Sarcoma of the Kidney (CCSK-case1), a Cellular Mesoblastic Nephroma (CMN-case2) and a Metanephric Adenoma (MA-case3) and compare them, for differential diagnostic purposes, with smears of blastematous, mesenchymal and epithelial predominant WTs, previously diagnosed in our Department. In all cases a mass was detected in the abdomen (2 and 8 year old children-cases 1 and 3, respectively), and pre-birth in case 2 (the tumour was detected during pregnancy). Fine needle biopsy was performed followed by routine cytologic examination. The presence of moderate amount of blue pale cytoplasm in neoplastic cells (case1), the presence of tightly cohesive, bland, spindle tumour cells (case2) and the identification of small, well differentiated epithelial tubules with psammoma bodies in case 3, were the main morphologic characteristics that we think represent the most important elements for distinguishing our cases from a WT. Immunoreactivity was only helpful in case 1 as we found a characteristic dot-like pattern positivity for vimentin, in the absence of immunoreactivity for the other markers that are usually positive in WT. Summing up, these three cases demonstrate that cytopathologists should be aware of the occurrence of uncommon renal neoplasms in childhood and should be acquainted with their characteristics, in order to avoid false diagnoses.

Immunohistochemical detection of MDR proteins in Wilms' tumour.

OBJECTIVES: The aim of our work was to determine the expression of three MDR proteins (MDR1/Pgp, MRP1 and LRP/MVP) in 15 tissue samples of nephroblastoma (Wilms' tumour). BACKGROUND: The majority of Wilms' tumours respond well to chemotherapy and are successfully cured, but a small subset displays resistance to therapy. The molecular mechanisms of drug resistance in this tumour type of childhood are still poorly analyzed. In our opinion, the elucidation of reasons for therapy failure in nephroblastomas is urgently needed before cure becomes a reality for children with this cancer. METHODS: To demonstrate these proteins the enzyme indirect immunohistochemical method was used. The brown colour of the diaminobenzidine reaction product allowed us to define the distribution of stain clearly. CONCLUSION: Our immunohistochemical analysis did not demonstrate any expression of MDR1 in all cases of nephroblastoma (14 cases were after pre-operative chemotherapy, 1 case wasn't). The analysis of MRP1 and LRP expression in our set revealed 60% positivity for MRP1 and 26.7% positivity for LRP. The ability to recognize the multidrug resistance phenotype might assist in choosing specific chemotherapeutic regimens to improve prognosis and therapy (Tab. 2, Fig. 2, Ref. 20). Full Text (Free, PDF) www.bmj.sk.

[Expression of Stat3, HIF-1alpha and VEGF in Wilms' tumor].

OBJECTIVE: To study the expression of signal transducer and activator of transcription 3 (Stat3), hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in Wilms' tumor and their roles in the development of Wilms' tumor. METHODS: The expression of Stat3, HIF-1alpha and VEGF were detected by the immunohistochemical staining in 52 specimens from Wilms' tumor tissues, 47 from adjacent kidney tissues and 8 from normal kidney tissues. The expression intensity was analyzed by computer image processing. RESULTS: The expression of Stat3, HIF-1 and VEGF were significantly up-regulated in Wilms' tumor tissues compared to those in adjacent tissues and normal kidney tissues (P < 0.05). Stat3 and VEGF proteins in Wilms' tumor tissues of stage III-IV and high risk histopathology were significantly higher than those of stage I-II and low risk histopathology. The higher expression of HIF-1 in Wilms' tumor tissues was shown in tumors with high risk histopathology and tumor size > or = 6 cm. CONCLUSIONS: Increased expression of Stat3, HIF-1 and VEGF were found in Wilms' tumor tissues, and may be related to the development and angiogenesis of Wilms' tumor. Stat3 may regulate the expression of HIF-1 and VEGF, so it could be an effective target for inhibiting VEGF expression and angiogenesis of Wilms' tumor.

Impact of Wilms' tumor 1 expression on outcome of patients undergoing allogeneic stem cell transplantation for AML.

The monitoring of the minimal residual disease by Wilms' tumor 1 expression (MRDWT1) is a standardized test, which can be used in over 80% of patients with AML. To investigate the prognostic value of MRDWT1 in patients undergoing allogeneic stem cell transplantation (allo-SCT) for AML, MRDWT1 was monitored 3 months after transplantation in 139 patients. MRDWT1 positivity did not lead to any therapeutic intervention. Median follow-up was 39.3 (6.4-99.8) months. Patients with positive MRDWT1 at 3 months experienced more often post-transplant relapse (27/30, 90%) than those with negative MRDWT1 (16/109, 14.7%) (P<0.0001). Similarly, a shorter 3-year event-free survival (EFS) was observed in MRDWT1-positive patients (10% vs 72.3% in MRDWT1-negative patients, P<0.0001). The correlation between relapse and MRDWT1 was stronger in blood than in bone marrow samples. Multivariate analysis confirmed the detrimental role of 3-month positive MRDWT1 for relapse (hazard ratio (HR): 15.42; 95% confidence interval (CI): 7.53-31.59; P<0.0001) and EFS (HR: 10.71; 95% CI: 5.41-21.21; P<0.0001). Interestingly, 3-month chimerism was less predictive of relapse than positive MRDWT1. In conclusion, our results demonstrate the usefulness of peripheral blood MRDWT1 monitoring in identifying very high-risk patients, who could benefit from an early preemptive treatment, and those who do not need such an intervention.

Diagnostic utility of cyclin D1 in the diagnosis of small round blue cell tumors in children and adolescents.

Small round blue cell tumors (SRBCTs) of children and adolescents are often diagnostically challenging lesions. With the increasing diagnostic approach based on small biopsies, there is the need of specific immunomarkers that can help in the differential diagnosis among the different tumor histotypes to assure the patient a correct diagnosis for proper treatment. Based on our recent studies showing cyclin D1 overexpression in both Ewing sarcoma/primitive peripheral neuroectodermal tumor (EWS/pPNET) and peripheral neuroblastic tumors (neuroblastoma and ganglioneuroblastoma), we immunohistochemically assessed cyclin D1 immunoreactivity in 128 cases of SRBCTs in children and adolescents to establish its potential utility in the differential diagnosis. All cases of EWS/pPNET and the undifferentiated/poorly differentiated neuroblastomatous component of all peripheral neuroblastic tumors exhibited strong and diffuse nuclear staining (>50% of neoplastic cells) for cyclin D1. In contrast, this marker was absent from rhabdomyosarcoma (regardless of subtype) and lymphoblastic lymphoma (either B- or T-cell precursors), whereas it was only focally detected (<5% of neoplastic cells) in some cases of Wilms tumor (blastemal component) and desmoplastic small round cell tumor. Our findings suggest that cyclin D1 can be exploitable as a diagnostic adjunct to conventional markers in confirming the diagnosis of EWS/pPNET or neuroblastoma/ganglioneuroblastoma. Its use in routine practice may also be helpful for those cases of SRBCT with undifferentiated morphology that are difficult to diagnose after application of the conventional markers.

Expression and adhesive activity of SC1, an Ig superfamily cell adhesion molecule, in sporadic nephroblastomas of chicken.

SC1, an immunoglobulin superfamily cell adhesion molecule, is transiently expressed during avian embryogenesis by a variety of cell types. This molecule has a homophilic binding activity with SC1 itself and promotes neurite projection from embryonic neurons. However, the potential role of this molecule in pathologic tissue specimens from chickens has yet to be elucidated. In this study, we examined the expression and functional role of SC1 in the sporadic nephroblastomas of chickens. Western blot analysis showed SC1 to be recognized as approximately 100 kDa and enriched in embryonic metanephros with a lower level in the adult kidney, while it was overexpressed in nephroblastomas. Immunohistochemically, SC1 was abundantly found in the tubular epithelia and blastemal cells of embryonic metanephros. In contrast, it had almost completely disappeared in the adult kidney; parts of the distal convoluted and intermediated tubules, collecting ducts, and Bowman's capsule slightly expressed SC1. In all 32 cases of nephroblastoma, SC1 was overexpressed in most characteristic components in tumors such as neoplastic epithelia with various types of differentiation, blastemal cell condensations, and glomeruloid bodies. Primary culture cells from a nephroblastoma expressed SC1 on the cell surface, whereas cells from the adult kidney showed only weak expression. A cell aggregation assay revealed that the dissociated cells from a nephroblastoma have strong aggregation activity, which was inhibited by anti-SC1 antibody. In contrast, the self-aggregation of adult chicken kidney cells was weaker than that of the tumor and not inhibited by the antibody. These findings suggest that the expression of SC1 might play a potential role in both the structural formation of nephroblastomas, based on its adhesive activity, and normal renal development.