Outcome of Nephroblastoma Treatment According to the SIOP-2001 Strategy at a Single Institution in Argentina.

OBJECTIVE: Wilms tumor (WT) is a disease with a good prognosis. The aim of this study was to evaluate the outcome of patients with WT, treated according to the SIOP-2001 strategy. METHODS: A retrospective analysis of 141 consecutive patients with WT diagnosed at our institution between December 2001 and 2013 was performed. RESULTS: A total of 114 patients, median age 38.8 months (3 to 155 mo), were assessable for analysis. Fine-needle aspiration was initially performed in 88 patients (84.6%). Stage distribution was: I: 33%, II: 9.6%, III: 28%, IV: 14%, V: 14.9%. Six patients were stage III because of tumor spillage. The remaining patients received preoperative chemotherapy. Adjuvant chemotherapy was given without randomization, using vincristine-actinomycin for stage II and vincristine-doxorubicin-actinomycin plus radiotherapy for stage III. After a median follow-up of 52 months, 5-year overall survival and event-free survival were 91% and 85%, respectively. Overall survival according to stage was: I: 96%, II: 99%, III: 88%, IV: 78%, V: 90% (P=0.16). There was no significant difference in event-free survival (P=0.7). Seventy-eight (85.7%) were intermediate-risk and 11 (12%) were high-risk patients. Seventeen patients (14.9%) relapsed within 2 to 99 months (median 29.9 mo). Eight patients (7%) died of progressive disease. There were no treatment-related deaths. CONCLUSIONS: The SIOP-01 protocol proposes a treatment strategy that is feasible in our institution, achieving good results.

Children and Adolescent Hodgkin Lymphoma in Argentina: Long-term Results After Combined ABVD and Restricted Radiotherapy.

OBJECTIVE: Prospective analysis of clinical characteristics and long-term treatment results of a pediatric cohort with Hodgkin lymphoma (HL) treated in a single institution with ABVD and restricted radiotherapy (RT). PATIENTS AND METHODS: Between September 2000 and December 2015, 165 new consecutive assessable patients with HL were registered at our institution. Lymphocyte predominant nodular HL was excluded. Low risk (LR) patients were stage I and IIA (no bulky disease, <4 involved ganglionar areas and no lung hilar nodes), high risk (HR) was assigned to stage IV and any other stage with bulky mediastinum. The rest of the cohort was treated as intermediate risk (IR). Chemotherapy for LR and IR patients was 4 and 6 courses of ABVD regimen, respectively. These subsets received Low-dose involved field radiotherapy only in case of partial remission at the end of chemotherapy (21 Gy in initially involved areas, plus 14 Gy boost on residual disease). The HR group was treated with 6 courses of ABVD followed always with 21 Gy involved field radiotherapy if complete remission (CR) was achieved. A boost of 14 Gy was added to residual disease in case of partial remission. RESULTS: Median age was 10.6 years (range, 2.7 to 17 y). Males: 117 (71%); females: 48 (29%). Eighteen (11%) patients were stage I, 76 (46%) stage II, 35 (21%) stage III, and 35 (21%) stage IV. Forty-nine (30%) patients were assigned to LR, 49 (30%) to IR, and 67 (40%) to HR. Forty-three patients (26%) had "bulky" mediastinum involvement. One hundred thirty (79%) patients achieved CR after chemotherapy and 161 (98%) after RT. Four patients (all HR), did not respond to initial therapy and died of disease. One patient died in first CR due to adenovirus infection on previously therapy-related damaged lungs. Seventeen (10%) patients relapsed and 13 of them remained in second CR after further therapy. Seventy-six (46%) patients could be spared from RT and cured of disease (88% of LR patients and 67% of IR patients). With a median follow-up of 5 years, event free and overall survival were 0.84 (SE: 0.03) and 0.95 (SE: 0.02), respectively. Overall survival according to risk group was 1 for LR, 0.93 for IR, and 0.85 for HR. Acute toxicity and late effects due to therapy were not significant. CONCLUSIONS: The strategy of avoiding RT for LR and IR patients that responded completely to ABVD chemotherapy achieved very good results. For the HR group, the combination of 6 cycles of ABVD and Low-dose involved field radiotherapy was efficacious with similar good results. Nearly half of the patients could be cured without RT.

Second Neoplasms in Children Following a Treatment for Acute Leukemia and/or Lymphoma: 29 Years of Experience in a Single Institution in Argentina.

INTRODUCTION: Childhood acute leukemias (AL) and lymphomas achieve good survival rates. However, second neoplasms (SN) are a devastating event. METHODS: From August 1987 to December 2016, 34 of 3321 (1%) patients with diagnosis of AL or lymphoma developed SN. SN were AL (n=16), CNS tumors (n=5), endocrinal tumors (n=3), lymphomas (n=2), schwannoma (n=2) assorted sarcomas (n=4), retinal melanoma (n=1), and Vanek tumor (n=1). Median latency was 51 (range, 10 to 110) months for hematological malignancies and 119 (range, 25 to 236) months for solid tumors (P=0.001). RESULTS: A total of 33 patients with SN were treated taking into account cumulative doses of anthracyclines and radiotherapy. Twenty-three (67.6%) patients achieved complete remission (CR), 5 died early during therapy and 5 were refractory or partial responders. Six patients presented relapses of the SN and 1 died in CR. Seventeen patients remain alive in CR, with a median follow-up of 110 (range, 4 to 276) months. CONCLUSIONS: (1) The latency period was significantly longer for patients developing solid tumors than for those developing AL. (2) AL was the most frequent SN. (3) Our results strongly encourage giving standard therapy to SN, considering cumulative doses of previous treatment, since similar probabilities of surviving as "de novo" counterparts can be achieved.

A Phase I Study of the Anti-Idiotype Vaccine Racotumomab in Neuroblastoma and Other Pediatric Refractory Malignancies.

BACKGROUND: Pediatric neuroectodermal malignancies express N-glycolylated gangliosides including N-glycolyl GM3 (NeuGcGM3) as targets for immunotherapy. PROCEDURE: We evaluated the toxicity and maximum tolerated dose and immunological response of racotumomab, an anti-idiotype vaccine targeting NeuGcGM3 through a Phase I study enrolling children with relapsed or resistant tumors expressing NeuGcGM3. MATERIALS AND METHODS: Drug dose was escalated to three levels (0.15-0.25-0.4 mg) of racotumomab administered intradermally. Each drug level included three patients receiving a total of three doses, every 14 days. A confirmation cohort was added to the highest dose level. Antibody response was assessed upon study entry and at 4-week intervals for at least three immunological determinations for each patient. RESULTS: Fourteen patients were enrolled (10 with neuroblastoma, one with retinoblastoma, one with Wilms' tumor, and two with brainstem glioma). Three patients completed the three drug levels and three were enrolled in the confirmation cohort. One patient died of tumor progression before completing the three applications. Racotumomab was well tolerated. The only side effect observed was grade 1-2 toxicity at the injection site. Racotumomab elicited an IgM and/or IgG antibody response directed against NGcGM3 in nine patients and IgM against racotumomab in 11 of 13 evaluable patients. The maximum tolerated dose was not reached and no dose-limiting toxicity was seen. CONCLUSIONS: Racotumomab vaccination has a favorable toxicity profile up to a dose of 0.4 mg, and most patients elicited an immune response. Its activity as immunotherapy for neuroectodermal malignancies will be tested in further clinical trials.

Genetic Deletion and Pharmacological Inhibition of PI3K γ Reduces Neutrophilic Airway Inflammation and Lung Damage in Mice with Cystic Fibrosis-Like Lung Disease.

PURPOSE: Neutrophil-dominated airway inflammation is a key feature of progressive lung damage in cystic fibrosis (CF). Thus, reducing airway inflammation is a major goal to prevent lung damage in CF. However, current anti-inflammatory drugs have shown several limits. PI3Kγ plays a pivotal role in leukocyte recruitment and activation; in the present study we determined the effects of genetic deletion and pharmacologic inhibition of PI3Kγ on airway inflammation and structural lung damage in a mouse model of CF lung disease. METHODS: ßENaC overexpressing mice (ßENaC-Tg) were backcrossed with PI3Kγ-deficient (PI3Kγ (KO)) mice. Tissue damage was assessed by histology and morphometry and inflammatory cell number was evaluated in bronchoalveolar lavage fluid (BALF). Furthermore, we assessed the effect of a specific PI3Kγ inhibitor (AS-605240) on inflammatory cell number in BALF. RESULTS: Genetic deletion of PI3Kγ decreased neutrophil numbers in BALF of PI3Kγ (KO)/ßENaC-Tg mice, and this was associated with reduced emphysematous changes. Treatment with the PI3Kγ inhibitor AS-605240 decreased the number of neutrophils in BALF of ßENaC-Tg mice, reproducing the effect observed with genetic deletion of the enzyme. CONCLUSIONS: These results demonstrate the biological efficacy of both genetic deletion and pharmacological inhibition of PI3Kγ in reducing chronic neutrophilic inflammation in CF-like lung disease in vivo.

Clinical presentation of non-malignant diseases mimicking leukemia cutis: A report of two cases. / Presentación clínica de patologías no malignas que simulan leucemia cutis: a propósito de dos casos.

The infiltration of leukemia cells into the skin, known as leukemia cutis, is a rare presentation of this disease and accounts for a diagnostic challenge. The main differential diagnoses include infections, other neoplastic diseases with skin involvement and histiocytic disorders, among others, as they entail different prognostic and therapeutic approaches. Here we describe two patients who were initially diagnosed with leukemia cutis, whose final diagnosis was of non-malignant diseases.

La infiltración cutánea por células leucémicas conocida como leucemia cutis es una presentación infrecuente de esta patología y constituye un desafío diagnóstico. Los diagnósticos como infecciones, otras patologías neoplásicas con afectación cutánea y los trastornos histiocíticos, entre otros, constituyen los principales diagnósticos diferenciales, ya que configuran un escenario pronóstico y terapéutico diferente. Se presentan dos pacientes que fueron diagnosticados inicialmente como leucemia cutis, cuyo diagnóstico final fue de patologías no malignas.

Generalized Lymphatic Anomaly as a Differential Diagnosis of Lytic Lesions.

Generalized lymphatic anomaly (GLA) is an infrequent multiorgan disease characterized by the presence of abnormal proliferation of lymphatic vessels. The diagnosis requires histological confirmation, and the treatment is controversial. We are presenting a case of a 28-year-old male patient who was diagnosed with an extragonadal mediastinal nonseminomatous germ cell tumor. He underwent chemotherapy, and during this treatment, radiologic findings evidenced lytic lesions. Multiple biopsies were performed, which revealed the presence of abnormal lymphatic vessels, characteristic of GLA. There are different etiologies of osteolytic lesions, and on some occasions, they mimic a tumoral entity. The clinical suspicion of GLA is the first step in approaching the diagnosis, particularly in young adult patients.

A Surgical and Clinical Approach to Persistent Müllerian Duct Syndrome: Laparoscopic, Histological, and Molecular Findings.

BACKGROUND: Persistent müllerian duct syndrome (PMDS) is characterized by the persistence of müllerian duct derivatives in otherwise normally virilized 46,XY males. Biallelic mutations of the anti-müllerian hormone (AMH) and AMH receptor type 2 (AMHR2) genes lead to PMDS type 1 and 2, respectively. AIM: The aims of the study were to report the clinical, hormonal, and genetic findings in a patient with PMDS and discuss surgical strategies to achieve successful orchidopexy. RESULTS: A 4-year-old boy was evaluated after the incidental finding of müllerian derivates during laparoscopy for nonpalpable gonads. Karyotype was 46,XY and laboratory tests revealed normal serum gonadotropin and androgen levels but undetectable serum AMH levels. PMDS was suspected. Molecular analysis revealed a novel variant c.902_929del in exon 5 and a previously reported mutation (c.367C>T) in exon 1 of the AMH gene. Successful orchidopexy was performed in two sequential surgeries in which the müllerian duct structure was preserved and divided to protect the vascular supply to the gonads. Histological evaluation of the testicular biopsy showed mild signs of dysgenesis. Doppler ultrasound showed blood flow in both testes positioned in the scrotum 1.5 years after surgery. CONCLUSION: PMDS is a rare entity that requires a high index of suspicion (from surgeons) when evaluating a patient with bilateral cryptorchidism. Surgical treatment is challenging and long-term follow-up is essential. Histological evaluation of the testis deserves further investigation.

Hypoxia promotes invasive growth by transcriptional activation of the met protooncogene.

Hypoxia unleashes the invasive and metastatic potential of tumor cells by largely unknown mechanisms. The Met tyrosine kinase, a high affinity receptor for hepatocyte growth factor (HGF), plays a crucial role in controlling invasive growth and is often overexpressed in cancer. Here we show that: (1) hypoxia activates transcription of the met protooncogene, resulting in higher levels of Met; (2) hypoxic areas of tumors overexpress Met; (3) hypoxia amplifies HGF signaling; (4) hypoxia synergizes with HGF in inducing invasion; (5) the proinvasive effects of hypoxia are mimicked by Met overexpression; and (6) inhibition of Met expression prevents hypoxia-induced invasive growth. These data show that hypoxia promotes tumor invasion by sensitizing cells to HGF stimulation, providing a molecular basis to explain Met overexpression in cancer.

Monovalency unleashes the full therapeutic potential of the DN-30 anti-Met antibody.

Met, the high affinity receptor for hepatocyte growth factor, is one of the most frequently activated tyrosine kinases in human cancer and a validated target for cancer therapy. We previously developed a mouse monoclonal antibody directed against the extracellular portion of Met (DN-30) that induces Met proteolytic cleavage (receptor "shedding") followed by proteasome-mediated receptor degradation. This translates into inhibition of hepatocyte growth factor/Met-mediated biological activities. However, DN-30 binding to Met also results in partial activation of the Met kinase due to antibody-mediated receptor homodimerization. To safely harness the therapeutic potential of DN-30, its shedding activity must be disassociated from its agonistic activity. Here we show that the DN-30 Fab fragment maintains high affinity Met binding, elicits efficient receptor shedding and down-regulation, and does not promote kinase activation. In Met-addicted tumor cell lines, DN-30 Fab displays potent cytostatic and cytotoxic activity in a dose-dependent fashion. DN-30 Fab also inhibits anchorage-independent growth of several tumor cell lines. In mouse tumorigenesis assays using Met-addicted carcinoma cells, intratumor administration of DN-30 Fab or systemic delivery of a chemically stabilized form of the same molecule results in reduction of Met phosphorylation and inhibition of tumor growth. These data provide proof of concept that monovalency unleashes the full therapeutic potential of the DN-30 antibody and point at DN-30 Fab as a promising tool for Met-targeted therapy.

Presentación clínica de patologías no malignas que simulan leucemia cutis: a propósito de dos casos / Clinical presentation of non-malignant diseases mimicking leukemia cutis: A report of two cases

La infiltración cutánea por células leucémicas conocida como leucemia cutis es una presentación infrecuente de esta patología y constituye un desafío diagnóstico. Los diagnósticos como infecciones, otras patologías neoplásicas con afectación cutánea y los trastornos histiocíticos, entre otros, constituyen los principales diagnósticos diferenciales, ya que configuran un escenario pronóstico y terapéutico diferente. Se presentan dos pacientes que fueron diagnosticados inicialmente como leucemia cutis, cuyo diagnóstico final fue de patologías no malignas.

The infiltration of leukemia cells into the skin, known as leukemia cutis, is a rare presentation of this disease and accounts for a diagnostic challenge. The main differential diagnoses include infections, other neoplastic diseases with skin involvement and histiocytic disorders, among others, as they entail different prognostic and therapeutic approaches. Here we describe two patients who were initially diagnosed with leukemia cutis, whose final diagnosis was of non-malignant diseases.

A composite renal tumor: metanephric adenofibroma, Wilms tumor, and renal cell carcinoma: a missing link?

A coexistence of different renal tumors has rarely been reported. The most commonly described association is of Wilms tumor and renal cell carcinoma. Metanephric adenofibroma has also been associated with Wilms tumor or papillary renal cell carcinoma. Another reported association is metanephric adenoma and papillary renal cell carcinoma with sarcomatoid dedifferentiation. Herein we describe a complex renal tumor containing areas of metanephric adenofibroma, Wilms tumor, and undifferentiated renal cell carcinoma in a previously healthy 18-year-old boy. The tumor showed histologic and immunohistochemical features of these 3 different tumors, offering additional support to the view that these 3 tumors are related.

Bone marrow findings at diagnosis in patients with multisystem langerhans cell histiocytosis.

This study was designed to describe the bone marrow features of multisystem Langerhans cell histiocytosis (LCH) at diagnosis in patients with or without hematologic dysfunction. A retrospective review of bone marrow biopsies from patients with multisystem LCH was performed. Cases were diagnosed at the Garrahan Hospital between 1987 and 2004. Routine and immunohistochemistry techniques (hematoxylin-eosin, periodic acid-Schiff, Giemsa, Gomori reticulin, and CD1a, CD68, and CD61) were evaluated. Clinical outcome and laboratory data were obtained from the medical charts. Twenty-two bone marrow biopsies from patients with multisystem LCH were reviewed at onset of disease. Four patients had no hematologic dysfunction and the other 18 patients had monocytopenia (9), bicytopenia (7), or tricytopenia (2). Increased number and dysplasia of megakaryocytes were evident in 22/22 samples and emperipolesis was present in 21/22 (95%). Aggregates of histiocytes and hemophagocytosis were seen in 9/22 samples. Myelofibrosis was found in 16/17 (94%) evaluable samples at diagnosis. No association of myelofibrosis and cytopenias or clinical outcome was found. Positive CD1a confirmed the presence of LCH cells in 3/22 (14%) samples. Hemophagocytosis and poor outcome were significantly more common in patients with bilineage and trilineage cytopenias. Langerhans cell histiocytosis cells were rarely seen in the bone marrow of these patients (14%); increased histiocytes and hemophagocytosis were more commonly found (41%). Hemophagocytosis was associated with severe cytopenias. Bicytopenia and tricytopenia were associated with poor outcome (death). Myelofibrosis, megakaryocytic dysplasia, and emperipolesis were common findings.

Prevention of hypoxia by myoglobin expression in human tumor cells promotes differentiation and inhibits metastasis.

As a tumor grows, it requires increased amounts of oxygen. However, the tumor blood vessels that form to meet this demand are functionally impaired, leading to regions of hypoxia within the tumor. Such hypoxia is one of the hallmarks of malignancy and is thought to promote a number of tumorigenic properties. Here, we sought to determine how tumors without hypoxia would progress by engineering A549 human lung carcinoma cells to ectopically express myoglobin (Mb), a multifunctional heme protein that specializes in oxygen transport, storage, and buffering. Mb expression prevented the hypoxic response in vitro and delayed tumor engraftment and reduced tumor growth following xenotransplantation into mice. Experimental tumors expressing Mb displayed reduced or no hypoxia, minimal HIF-1alpha levels, and a homogeneously low vessel density. Mb-mediated tumor oxygenation promoted differentiation of cancer cells and suppressed both local and distal metastatic spreading. These effects were primarily due to reduced tumor hypoxia, because they were not observed using point-mutated forms of myoglobin unable to bind oxygen and they were abrogated by expression of a constitutively active form of HIF-1alpha. Although limited to xenograft models, these data provide experimental proof of the concept that hypoxia is not just a side effect of deregulated growth but a key factor on which the tumor relies in order to promote its own expansion.

A high affinity hepatocyte growth factor-binding site in the immunoglobulin-like region of Met.

Hepatocyte growth factor (HGF) and its high affinity receptor, the tyrosine kinase Met, play a key role in embryo development and tumor invasion. Both HGF and Met are established targets for cancer therapy. However, the mechanism of their interaction is complex and remains elusive. HGF is secreted as a monomeric precursor (pro-HGF) that binds to but does not activate Met. Mature HGF is a alpha/beta heterodimer containing a high affinity Met-binding site in the alpha-chain (HGF-alpha) and a low affinity Met-binding site in the beta-chain (HGF-beta). The extracellular portion of Met contains a semaphorin (Sema) domain, a cysteine-rich hinge (plexin-semaphorin-integrin), and four immunoglobulin-like domains (immunoglobulin-like regions in plexins and transcription factors (IPT) 1-4). HGF-beta binds to Sema through a low affinity contact. The domain of Met responsible for high affinity binding to HGF-alpha has not been identified yet. Here we show that this long sought after binding site lies in the immunoglobulin-like region of Met and more precisely in IPT 3 and 4. We also show that IPT 3 and 4 are sufficient to transmit the signal for kinase activation to the cytoplasm, although the lack of Sema makes the receptor equally sensitive to mature HGF and pro-HGF. Finally, we provide evidence that soluble Met-derived proteins containing either the low affinity or high affinity HGF-binding site antagonize HGF-induced invasive growth both in vitro and in xenografts. These data suggest that the immunoglobulin-like region of Met cooperates with the Sema domain in binding to HGF and in controlling Met kinase activity. Although the IPT-HGF-alpha interaction provides binding strength, the Sema-HGF-beta contact confers selective sensitivity to the active form of the ligand.