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Germ cell tumors (GCTs) are a rare group of neoplasms that arise from pluripotent stem cells. They display variable behavior depending on age, histology, primary tumor site, and stage of disease. In pediatric GCTs serum alfa fetoprotein (AFP) is the most frequently used marker for diagnosis and monitoring, although it is not specific only for these diseases. In this review, we discuss extracranial GCTs and the usefulness of AFP in their management. [ABSTRACT FROM AUTHOR]

Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood, originating froma neoplastic deviation of B or T lymphocyte. Cytogenetic, cytofluorimetric, and genomic analyses clearly defined several subtypes of ALL. However, the leukemogenic process is characterized by different pathways' alteration which are still to be determined, in the attempt to identify specific targets to be druggable. In this review, we explore the main molecular pathways, which are commonly shared between different subtypes of pediatric ALL. These cell-signaling pathways affect many functions, including cell proliferation, apoptosis, migration, and differentiation. The PI3K/AKT/mTOR pathway is one of the most studied, with higher expected promises of being targetable. RAS pathway is also widely studied in all types of cancer. TheWnt/Beta catenin has been recently studied in ALL. Finally, CXCL12/CXCL4 axis has a crucial role in regulating hematopoietic stem cell and bone marrow niche. The complete characterization of these pathways will allow us to design a specific patient-disease profile associated with a tailored treatment, with the highest grade of efficacy and the lowest grade of toxicity. [ABSTRACT FROM AUTHOR]

Due to its many clinical and biologic characteristics, neuroblastoma (NB) is a polyhedric neoplasm. It is a very complex, extremely heterogeneous disease that can regress spontaneously even without therapy. However, it frequently shows a very aggressive behavior, refractory to current intensive multimodal therapy. The tumor, originating from primordial neural crest cells, is biochemically unique for its metabolic pathways of catecholamine synthesis and metabolism. Homovanillic acid (HVA), the main metabolite of dopamine, and vanillylmandelic acid (VMA), the main metabolite of adrenalin and noradrenalin, are sensitive and convenient markers of NB since they are found in large amounts in patient's urine. The rate of NB patients with positive VMA and/or HVA at the diagnosis varies with the stage of the disease, with high-stage tumors being more likely to have abnormal levels. Other less specific NB tumor serummarkers are neuron-specific enolase, ferritin, and lactate dehydrogenase. NB is one of the few pediatric tumors in which tumor markers have been shown to have a role in the diagnosis, prognosis, and disease monitoring. [ABSTRACT FROM AUTHOR]

The tumor lysis syndrome (TLS) is an oncology emergency triggered by a massive and abrupt release of intracellular substances (potassium, phosphate, and purine metabolites) into the bloodstream. It may occur spontaneously or, more frequently, as a consequence of chemotherapy or radiation therapy. When the accumulation of these metabolites overwhelms the normal homeostatic mechanism, the TLS develops and leads to hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcaemia. These metabolic derangements can progress to clinical manifestations including acute renal failure, cardiac arrhythmias, central nervous system toxicity, and even death. The key to prevent and manage TLS is the identification of high-risk patients to give them appropriate treatment measures when necessary. [ABSTRACT FROM AUTHOR]

Neuroblastoma is themost common extracranial solid tumor in childhood, arising in the sympathetic nervous system, metastatic in half of the patients at diagnosis, with bone and bonemarrow as themost frequent sites involved. Most neuroblastomas express the noradrenalin transporter molecule and take up metaiodobenzylguanidine (mIBG), providing a sensitive and specific method of assessing primary tumor and metastatic sites (soft tissue, bone marrow, and bone) when labeled with iodine-123, both at diagnosis, for staging, and as a prognostic factor for evaluation of response to therapy, especially when a semiquantitative scoring method is used. mIBG labeled with iodine-131 has demonstrated activity for targeted therapy of neuroblastoma in both relapsed and newly diagnosed patients, and is being used in clinical trials to optimize treatment of high-risk patients. [ABSTRACT FROM AUTHOR]

Pediatric adrenocortical tumors (ACTs) are rare in children. Most tumors are hormonally active with overproduction of androgens and glucocorticoids, and less frequently mineralocorticoids and estrogens. Patients usually present with clinical signs of virilization or Cushing syndrome, while only a minority of ACTs are incidentally discovered. Unfortunately, the clinical behavior of pediatric ACTs is often unpredictable, and the distinction between benign and malignant tumors is still challenging. The present review deals with the main clinical and laboratory features which can help to diagnose pediatric ACTs, with special emphasis on the pathological criteria useful to stratify patients into three different prognostic categories: (1) patients with benign tumors; (2) patients with malignant tumors; and (3) patients with borderline tumors (tumors with indeterminate malignancy). In this regard, general guidelines and histological illustrations are provided to offer a practical approach for a correct identification of morphological predictors of clinical outcome. [ABSTRACT FROM AUTHOR]

The article introduces various topics discussed in the present issue, including pediatric tumors, the need for a multidisciplinary approach, and an overview on adrenocortical tumors in childhood.