Clinical Research Directory

* Age ≥ 60 * Completed chemotherapy and/or radiation therapy and are being followed at Princess Margaret Cancer Centre i) Patient must be in remission for \> 3 months after completing chemotherapy or radiation ii) Predicted 5 year survival of \>75% iii) Peripheral blood counts must have returned to normal as defined by: 1. Platelets ≥ 100 x 109/L 2. PMN ≥ 1 x 109/L Or * Prior to chemotherapy and/or radiation therapy at the Princess Margaret Cancer Centre. * All histologically/cytologically proven tumour types (solid tumours and hematologic malignancies) will be eligible. * Received or will receive regimens of chemotherapy or radiation with doses expected to produce transient myelosuppression (PMN\<0.5x109/L) in at least 80% of treated patients (The identification and definition of appropriate myelosuppressive chemotherapy and radiation regimens will be at the discretion of the treating physician and will vary among disease sites). * Patients must have the ability to understand the requirements of the study and provide written informed consent, which includes authorization for release of protected health information * Patient must be willing to provide a peripheral blood sample. Exclusion Criteria: * Any other condition that would, in the Investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns or compliance with clinical study procedures.