[Identification of epithelial-mesenchymal transition markers (EMT) by immunohistochemistry in pediatric osteosarcoma and association with clinical outcomes]. / Identificación de marcadores de transición epitelio-mesénquima (TEM) por inmunohistoquímica en osteosarcoma pediátrico y asociación con desenlaces clínicos.

The epithelial-mesenchymal transition (EMT) is the ability of epithelial and mesenchymal cells to exchange phenotypes transiently. Its identification in carcinomatous cells has been associated with aggressive clinical phenotypes. In sarcomas, this ability is under study. OBJECTIVE: to evaluate the expression of two transcription factors involved in EMT by immunohistochemistry in pediatric osteosarcoma and its association with clinical outcomes. PATIENTS AND METHOD: A retrospective cohort study in children under 18 years of age with osteosarcoma diagnosis. Immunohistochemistry was performed for Snail and Twist-1 expressions from samples collected at the time of diagnosis. Correlations between immunohistochemistry and the clinical outcomes and overall survival were performed. RESULTS: 53 patients were included. There were 26 positive cytoplasmic cases (49.1%) in Snail expression and were correlated with the presence of multiple metastases (p = 0.02) and distant bone metastases (p = 0.01). On the other hand, 45 cases (84.9%) were positive in Twist-1 expression in the nuclear location, showing no association with the analyzed clinical variables. CONCLUSIONS: Snail and Twist-1 were frequently expressed in pediatric cases of osteosarcoma. Cytoplasmic Snail was correlated with the presence of multiple metastatic disease and distant bone metastases. The positivity of both markers suggests the activation of these proteins as regulators of EMT events in this tumor, suggesting a role in the phenomena related to the clinical presentation of the disease.

Clinical Characteristics and Outcomes of a Cohort of Pediatric Oncohematologic Patients With COVID-19 Infection in the City of Bogotá, Colombia.

BACKGROUND: In children, the complications of severe acute respiratory syndrome coronavirus 2 infection occur less frequently than in adults but the characteristics of this disease in oncology patients are not well characterized. METHODS: This was a retrospective study in patients younger than 18 years of age with coronavirus disease 2019 (COVID-19) and cancer diagnoses between April and September 2020. Demographic variables, laboratory, and radiologic findings and complications of each case were identified. A descriptive analysis was performed. RESULTS: A total of 33 patients were identified; the median age was 10 years. Fifteen patients (42%) were in chemotherapy at the time of the infection diagnosis, in two patients the chemotherapy protocol was permanently suspended. The most common symptom was fever in 20 patients (60%). Seven patients (21.2%) showed mild pneumonia, four patients (12.1%) severe pneumonia, and three cases (9.0%) were classified as critical. In the evaluated cohort, five patients (15.1%) died, and in two of those, death was caused by COVID-19 infection. CONCLUSIONS: Children with an oncologic disease, the search for COVID cases should be oriented to patients with fever, including febrile neutropenia, the presence of respiratory symptoms, and the search for epidemiologic contact. A higher frequency of complications and mortality attributed to COVID-19, two in pediatric oncohematologic patients was found. Institutional strategies to detect the infection early and lower institutional infection are indicated.