Judith F. Margolin

TREM-1, MDL-1, and DAP12 expression is associated with a mature stage of myeloid development

The triggering receptor expressed on myeloid cells (TREM-1) and the myeloid DAP12-associating lectin (MDL-1) are two recently identified receptors which associate non-covalently with DAP12 to form receptor complexes involved in monocytic activation and inflammatory response. In this study, we investigated whether the expression of TREM-1, MDL-1, and DAP12 correlated with myelomonocytic differentiation. Northern and RT-PCR revealed a strong expression of TREM-1, MDL-1, and DAP12 in peripheral blood-derived CD14(+) mature monocytes in contrast to undifferentiated bone marrow CD34(+) stem cells, and in the differentiated versus undifferentiated U937 cells. TREM-1 and MDL-1 RNA expression was also more elevated in adult than fetal tissues and in normal than malignant cells. These findings suggest that the TREM-1/DAP12 and MDL-1/DAP12 signaling pathways are features of mature differentiated myelomonocytic cells. In addition, expression of an alternative mRNA TREM-1 splice variant (TREM-1sv) was detected that might translate into a soluble receptor with potential as a regulator of myeloid activation.

Histologic subtypes of hepatoblastoma are characterized by differential canonical Wnt and Notch pathway activation in DLK+ precursors

Hepatoblastoma is characterized by a diversity of differentiation patterns, some resembling stages of liver development, and occasionally associated with clinical behavior. Our hypothesis is that histologic microheterogeneity in hepatoblastoma correlates with molecular heterogeneity and reflects different stages of developmental arrest. We studied the activation status of the Wnt and Notch pathways and the differential expression of hepatocyte nuclear factor 4alpha, EGFR, and IGF2 genes, relevant to liver development and malignant transformation in histologic variants of hepatoblastoma. Eighty-seven percent of 32 hepatoblastoma cases studied carried CTNNB1 mutations within the ubiquitination domain. Large deletions were seen only in pure fetal cases, also characterized by CCND1 and GLUL (GS) overexpression. Hepatoblastomas with small-cell type appeared clearly distinct and were the only ones with negative GLUL expression. HES1 expression and HES1/AXIN2 used to measure Notch versus Wnt activation ratio were particularly elevated in pure fetal cases and were lowest in hepatoblastomas with small-cell component. Hepatocyte nuclear factor 4alpha was relatively elevated only in embryonal hepatoblastomas. DLK1, DKK, AXIN2, IGF2, and EGFR were increased in all subtypes. Our results support the hypothesis that hepatoblastoma microheterogeneity correlates with molecular heterogeneity. DLK1, a marker of bipotential oval cells, is consistently up-regulated in hepatoblastoma. Therefore, we speculate that hepatoblastomas may arise from a proliferating bipotential precursor. Wnt activation is prevalent in hepatoblastomas, most significantly in predominantly embryonal and mixed types, whereas Notch activation, needed for cholangiocytic differentiation at a more differentiated state, is highest in pure fetal hepatoblastomas. The relative Wnt versus Notch activation appears useful in stratifying different subtypes.

Differential expression of multiple unexpected genes during U937 cell and macrophage differentiation detected by suppressive subtractive hybridization

OBJECTIVE The objective of this study was to identify new markers of myelomonocytic differentiation using a sensitive technique that permits detection of rare differential gene expression. MATERIALS AND METHODS [corrected] Suppressive subtractive hybridization (SSH) was performed between the human myelomonocytic U937 cell line and 1 alpha, 25-dihydroxyvitamin D3 and transforming growth factor beta 1 differentiated U937 cells. cDNA clones with significant increased expression in differentiated U937 cells over nondifferentiated U937 cells were characterized by sequencing. [corrected] The pattern of differential gene expression obtained by SSH was confirmed by cDNA Southern and Northern blots on the undifferentiated vs. differentiated U937 cells, and by reverse transcriptase polymerase chain reaction on undifferentiated human CD34(+) stem cells isolated from bone marrow vs. peripheral blood CD14(+) mature monocytes. RESULTS Seven cDNAs never associated with in vitro U937 cell myelomonocytic differentiation (prolactin, 11-beta hydroxysteroid dehydrogenase [11 beta-HSD)] haptoglobin alpha (2FS)-beta precursor, GLIPR, RTVP, the RNA helicase P68, and spermidine-spermine N1-acetyltransferase) were identified. The first five of these genes previously were associated with immune function and the last two are important for intermediary metabolism. Differential expression was confirmed in CD34(+)/CD14(+) monocyte differentiation for all genes but 11 beta-HSD. CONCLUSIONS We identified six new markers of U937 cell differentiation, which also are differentially expressed during normal human myelomonocytic differentiation.

Gene expression profiling reveals signatures characterizing histologic subtypes of hepatoblastoma and global deregulation in cell growth and survival pathways

Hepatoblastoma is the most common malignant tumor of the liver of children worldwide. Histologically, hepatoblastomas show marked variation in the type and proportion of epithelial (fetal, embryonal, or small cell) and mesenchymal components with differing prognosis and response to therapy. The pure fetal-type hepatoblastoma, presenting as stage 1 and resectable, has the best prognosis, whereas the small cell histology has been associated with unfavorable outcome. Using gene expression profiling, we demonstrate that in addition to Wnt pathway deregulation, cell growth and survival pathways are also globally deregulated in hepatoblastomas. Furthermore, the different histologic subtypes are characterized by specific gene expression and pathway signatures that give insight into the degree of molecular heterogeneity that is present among these tumors. Although Wnt signaling pathway upregulation is common to all histologic types of hepatoblastoma, this pathway is even more significantly deregulated in aggressive hepatoblastomas. In addition, deregulation of MAPK signaling pathway and antiapoptotic signaling is preferentially upregulated in aggressive epithelial hepatoblastomas with a small cell component. The gene expression signatures reported here provide possible prognostic and diagnostic markers as well as therapeutic targets for this disease.

Hyperglycemia during Induction Therapy is Associated with Poorer Survival in Children with Acute Lymphocytic Leukemia

OBJECTIVES To investigate whether children with acute lymphocytic leukemia (ALL) who have development of hyperglycemia during induction may have worse relapse-free (RFS) and overall survival (OS) rates. STUDY DESIGN A review of 167 children diagnosed with ALL between 1999 to 2002 at Texas Childrens Hospital was performed. Blood glucose concentrations during induction therapy were reviewed; patients were assigned to 3 groups: euglycemia (blood glucose < 140 mg/dL), mild hyperglycemia (blood glucose between 140-200 mg/dL), and overt hyperglycemia (blood glucose > 200 mg/dL). RFS and OS among groups were compared by use of Kaplan-Meier and Cox-proportional hazard analyses, adjusting for potential confounding variables. RESULTS The median follow-up in survivors was 6 years; there were 18 deaths and 36 relapses. Overt hyperglycemia was seen in 56 (34%) patients. Patients with overt hyperglycemia had poorer RFS (68% +/- [SE] 6.7 vs 85% +/- 3.6, P = .025) and OS (74% +/- 6.1 vs 96% +/- 1.9, P < .0001) at 5 years than their counterparts. Patients with overt hyperglycemia had 6.2 times (95% CI 1.6-24.7, P = .01) greater risk for death, independent of risk group and type of steroid. CONCLUSIONS Overt hyperglycemia may be an independent predictor of survival in children with ALL.

Impact of PET-CT on involved field radiotherapy design for pediatric Hodgkin lymphoma†‡

To determine how the incorporation of PET‐CT changes radiotherapy treatment in pediatric Hodgkin lymphoma.

Pediatric Hodgkin Lymphoma: Are We Over-Scanning Our Patients?

Despite the favorable outcome of most pediatric patients with Hodgkin lymphoma (HL), there is rising concern about risks of carcinogenesis from both diagnostic and therapeutic radiation exposure for patients treated on study protocols. Although previous studies have investigated radiation exposure during treatment, radiation from post-treatment surveillance imaging may also increase the likelihood of secondary malignancies. All diagnostic imaging examinations involving ionizing radiation exposure performed for surveillance following completion of therapy were recorded for 99 consecutive pediatric patients diagnosed with HL from 2000 to 2010. Cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. In the first 2 years following completion of therapy, patients in remission received a median of 11 examinations (range 0–26). Only 13 of 99 patients relapsed, 11 within 5 months of treatment completion. No relapse was detected by 1- or 2-view chest radiographs (n = 38 and 296, respectively), abdomen/pelvis computed tomography (CT) scans (n = 211), or positron emission tomography (PET) scans alone (n = 11). However, 10/391 (2.6%) of chest CT scans, 4/364 (1.1%) of neck CT scans, and 3/47 (6.4%) of PET/CT scans detected relapsed disease. Thus, only 17 scans (1.3%) detected relapse in a total of 1358 scans. Mean radiation dosages were 31.97 mSv for Stage 1, 37.76 mSv for Stage 2, 48.08 mSv for Stage 3, and 51.35 mSv for Stage 4 HL. Approximately 1% of surveillance imaging examinations identified relapsed disease. Given the very low rate of relapse detection by surveillance imaging stipulated by current protocols for pediatric HL patients, the financial burden of the tests themselves, the high cure rate, and risks of second malignancy from ionizing radiation exposure, modification of the surveillance strategy is recommended.

Hyperglycemia during induction therapy is associated with increased infectious complications in childhood acute lymphocytic leukemia

Children with acute lymphocytic leukemia (ALL) are at high risk for developing hyperglycemia. Hyperglycemic adult ALL patients have shorter remissions, more infections, and increased mortality. No corresponding data are available in children. We hypothesized that children with ALL who become hyperglycemic during induction chemotherapy have an increased risk for infection during their first year of treatment.

Medical therapy for pediatric vascular anomalies.

Vascular anomalies (VAs) comprise a large variety of individual diagnoses that in different phases of treatment require a diverse number of medical specialists to provide optimal care. Medical therapies include agents usually associated with cancer chemotherapy, such as vincristine, as well more immunomodulatory types of drugs, such as glucocorticoids and sirolimus. These immunomodulating drugs are being successfully applied in cases that are typically categorized as vascular tumors, including kaposiform hemangioendothelioma (KHE) and tufted angioma (TA), as well as some of the more invasive types of vascular malformations (i.e., microcystic lymphatic malformations and blue rubber bleb nevus syndrome (BRBNS). These therapies need to be combined with good supportive care, which often involves anticoagulation, antimicrobial prophylaxis, and comprehensive pain and symptom-relief strategies, as well as appropriate drug monitoring and management of side effects of medical treatment. The optimal care of these patients frequently involves close collaboration between surgeons, interventional and conventional radiologists, medical subspecialists, and nurses.

Novel potential ALL low-risk markers revealed by gene expression profiling with new high-throughput SSH-CCS-PCR

The current systems of risk grouping in pediatric acute lymphoblastic leukemia (ALL) fail to predict therapeutic success in 10–35% of patients. To identify better predictive markers of clinical behavior in ALL, we have developed an integrated approach for gene expression profiling that couples suppression subtractive hybridization, concatenated cDNA sequencing, and reverse transcriptase real-time quantitative PCR. Using this approach, a total of 600 differentially expressed genes were identified between t(4;11) ALL and pre-B ALL with no determinant chromosomal translocation. The expression of 67 genes was analyzed in different cytogenetic ALL subgroups and B lymphocytes isolated from healthy donors. Three genes, BACH1, TP53BPL, and H2B/S, were consistently expressed as a significant cluster associated with the low-risk ALL subgroups. A total of 42 genes were differentially expressed in ALL vs normal B lymphocytes, with no specific association with any particular ALL subgroups. The remaining 22 genes were part of a specific expression profile associated with the hyperdiploid, t(12;21), or t(4;11) subgroups. Using an unsupervised hierarchical cluster analysis, the discriminating power of these specific expression profiles allowed the clustering of patients according to their subgroups. These genes could help to understand the difference in treatment response and become therapeutical targets to improve ALL clinical outcomes.