Oral complications are a frequent source of morbidity in patients undergoing cancer therapy. These include soft tissue lesions (e.g., ulcers and mucositis) resulting from malignant disease, immunosuppression and cytotoxic therapies, as well as, exacerbation of dental infections such as abscesses resulting from caries and gingival inflammation. Oral lesions are not only a source of oral discomfort, but also are potential sources of systemic spread of infections. Factors which may be involved in oral morbidity include oral health status specific malignant disease and treatment modalities such as radiation, chemotherapy (e.g., antibiotics, tumoricidal and immunosuppressive drugs), and bone marrow transplantation. Over the last decade, pediatric cancer therapies have achieved tremendous improvements in prognosis. Therefore, in children, long-term survival with complete remission is becoming more common than before. This improved survival has resulted in an increased awareness and interest in the long-term effects (e.g., effects on developing dentition) of the aggressive treatment regimens used to obtain remission. The purpose of this pilot study is to initiate clinical studies investigating oral risk factors associated with the acute and long-term oral complications of cancer and its treatment in children with leukemia. This one year study will establish a working data base to compare information gathered from comprehensive oral/dental evaluations to systemic health status and treatment regimen in pediatric leukemia patients being treated at the Children's Hospital of Alabama (TCH). Data accumulated during this study will be used to determine oral and systemic risk factors involved in the development of oral complications. Additionally, because oral infections during cancer therapy are often of Candidal etiology, this study will evaluate two methods of demonstrating the presence of Candida in the oral cavity for efficacy in predicting the occurrence of oral lesions. Saliva and oral cytology specimens will be collected for analysis upon acceptance into this study and then periodically to evaluate the efficacy in predicting the occurrence of oral/systemic Candidal infections. the oral/dental data accumulated will initiate a prospective longitudinal data base that will be used to study the efficacy and cost effectiveness of dental intervention protocols in leukemia patients at risk for oral complications. The goal of this study is to obtain a better understanding of the pathogenesis of oral complications in order to develop improved diagnosis and prevention protocols for pediatric oncology patients.