الفهرس 
Ewing SarcomaOnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
ES is a bone and soft tissue tumor that is named after James Ewing. It is the second most common malignant tumor of the bone affecting children and young adults (10–20 years of age). ES is a highly aggressive malignancy, with 70–80% survival for patients with localized disease and 30% for metastatic. Treatment includes chemotherapy, surgery and radiotherapy. Usually, ES presents with metastases as invisible foci in standard images (micrometastases). Therefore, managing them all by local measures is highly unlikely. Despite aggressive therapy, after completing all scheduled treatment, at least 25% of patients with primarily localized illness will relapse. The rate of recurrence is even higher for those with initial metastatic disease, with treatment failure in 50%-80% of patients depending on metastasis site. And this is why many researchers are looking for CTCs detection. Flow cytometry (FC) considered an alternative sensitive technique used commonly for the assessment of minimal residual disease (MRD) in hematological malignancy. It is also used in diagnosis and follow-up assessment of solid tumors such as breast and prostate cancer in adult patients and rhabdomyosarcoma and neuroblastoma in pediatric patients The CD99 surface antigen is a universal marker of ES cells participating in cell adhesion, proliferation, apoptosis and T-cell differentiation as well as highly expressed on T-cell lymphoblastic leukemia / lymphoma and other hematopoietic progenitors that also express CD45 in contrast to ES cells Therefore, the combination of antigens CD99+ve and CD45−ve can be used to assess ES tumor samples as in our study. The aims of this work are detection of CD99+ve, CD45-ve cells by flow cytometry before and during chemotherapy of ES and evaluation of their prognostic value. This prospective cohort study was carried out on 60 children with histologically proven Ewing sarcoma selected from inpatient department of Children Cancer Hospital-Egypt 57357 and 40 healthy children matched age and sex served as control group from November 2016 to April 2018. All newly diagnosed ES patients (localized and metastatic) were treated with COG protocol AEWS0031 intensified chemotherapy (including vincristine, doxorubicin and cyclophosphamide alternating with ifosfamide and etoposide) 2 weeks apart and GCS-F (Granulocyte colony stimulating factor).CD99+ve/CD45-ve cells were classified as “positive” in peripheral blood if they were above the upper limit observed in the control cases or negative” if they were below the upper limit observed in the control cases