1 EXHIBIT 21 LIST OF SUBSIDIARIES Company State of Organization - ------- --------------------- IMPACT Center of Albany, LLC Tennessee IMPACT Center of Bayonne, LLC New Jersey IMPACT Center of Billings, LLC Montana IMPACT Center of Fort Smith, LLC Tennessee IMPACT Center of Glendale, LLC Tennessee IMPACT Center of Mobile, LLC Tennessee IMPACT Center of Mt. Diablo, LLC Tennessee IMPACT Center of Northridge, LLC Tennessee IMPACT Center of St. Johns, LLC Tennessee IMPACT Center of Tri-City Medical Center, LLC Tennessee IMPACT Center of Washington, D.C., LLC Tennessee Response Oncology of Fort Lauderdale, Inc. Florida Response Oncology of Tamarac, Inc. Florida Response Oncology Management of South Florida, Inc. Tennessee