Primary study objectives include are to determine the pharmacodynamic (PD) profiles for treatment doses of dalteparin in pediatric subjects of different ages with cancer and venous thromboembolism (VTE), using anti-Xa (Xa) levels and a population PD analysis methodology, and to determine the median dose required to achieve therapeutic anti- Xa levels (0.5 to 1.0 International Units [IU]/mL) based on subject age and weight.