Cancer Organizations: M
- M S Ramaiah Memorial Hospital
- M. D. Anderson Cancer Center at University of Texas
- M. D. Anderson International Espana SA
- M.D. Anderson Cancer Center at Orlando
- M.D. Anderson Cord Blood Bank
- M.D. Oswal Cancer Treatment & Research Foundation
- M.P. Shah Cancer Hospital
- M.R. Hart Regional Radiation Center
- M.S.I. Foundation
- M.T.U. Cancer Institute
- MAPS Medical Pain Clinic - Edina
- MBCCOP - Gulf Coast
- MBCCOP - Hawaii
- MBCCOP - Howard University Cancer Center
- MBCCOP - JHS Hospital of Cook County
- MBCCOP - LSU Health Sciences Center
- MBCCOP - Massey Cancer Center
- MBCCOP - Medical College of Georgia Cancer Center
- MBCCOP - Meharry Medical College - Nashville
- MBCCOP - Our Lady of Mercy Comprehensive Cancer Center
- MBCCOP - San Juan
- MBCCOP - South Texas Pediatrics
- MBCCOP - University of Illinois at Chicago
- MBCCOP - University of New Mexico HSC
- MCH Urologic Associates, PC
- MD Specialists
- MDS Nordion
- MDS Pharma Services
- MED Institute, Incorporated
- MEDICE Arzneimittel Puetter GmbH & Co. KG
- MEDSchool Associates North
- MGI Pharma, Incorporated
- MIRO Farmington Hills Cancer Center
- MJP Urology
- MMPC Urology
- MNAP Oncologic Center
- MNJ Institute of Oncology and Regional Cancer Center
- MOH Micrographic Surgery at Helmwood Medical Center
- MRC Myelomatosis Trials Office
- MRI Diagnostics of Westchester
- MSD Pharmaceuticals Private Limited
- MSU Kalamazoo Center for Medical Studies
- Maasland Hospital
- Maastro Clinic - Locatie Heerlen
- Maastro Clinic - Locatie Maastricht
- Maastro Lab at University of Maastricht
- Maasziekenhuis Pantein
- Mabry Center for Cancer Care at Regional Medical Center
- MacDonald Physicians, Incorporated at University MacDonald Womens Hospital
- MacNeal Cancer Center at MacNeal Hospital
- Maccabi HMO
- Maccabi Health Services
- Maccabi Health Services
- Macclesfield District General Hospital
- Mackay Memorial Hospital
- Macon Cancer Center
- Maddock Center for Radiation Oncology
- Madigan Army Medical Center - Puyallup
- Madigan Army Medical Center - Tacoma
- Madison County Cancer Care Center
- Madison Surgical Associates, PC
- Madrona Medical Group
- Magee-Womens Surgical Associates at Magee-Womens Hospital
- Magnolia Radiation Oncology
- Magruder Hospital
- Maharaj Nakorn Chiang Mai Hospital
- Mahavir Cancer Sansthan
- Mahavir Surgical Hospital and Cancer Care Centre
- Mahmood-Schor Urology
- Mahoning Valley Cancer Center
- Mahoning Valley Hematology/Oncology Associates, Incorporated
- Mahopac Radiation Oncology
- Maidstone Hospital
- Mailman Center for Child Development
- Maimonides Cancer Center at Maimonides Medical Center
- Main Line Surgeons, Limited at Lankenau Hospital
- Maine Center for Cancer Medicine and Blood Disorders - Brunswick
- Maine Center for Cancer Medicine and Blood Disorders - Biddeford
- Maine Center for Cancer Medicine and Blood Disorders - Scarborough
- Maine Children's Cancer Program at Barbara Bush Children's Hospital
- Maine Heart Surgical Associates, P.A.
- Maine Medical Center - Bramhall Campus
- Maine Medical Center - Brighton Campus
- Maine Medical Center Research Institute
- Maine Surgical Care Group
- Maine Women's Surgery and Cancer Center at Maine Medical Center
- MaineGeneral Medical Center - Augusta
- MaineGeneral Medical Center - Waterville
- Maison Medicale Marzet
- Maisonneuve-Rosemont Hospital
- Makati Medical Center
- Malcolm Grow US Air Force Medical Center
- Malden Medical Center
- Male Health Centre - North York
- Male Health Centre - Oakville
- Male Health Centres - Barrie
- Mallinckrodt Institute of Radiology at Washington University Medical Center
- Mallya Hospital
- Malmo University Hospital
- Malteser Krankenhaus