Skip Navigation
Search Menu
Find an Expert


David Mark Loeb, M.D., Ph.D.

Photo of Dr. David Mark Loeb, M.D., Ph.D.

Director of the Musculoskeletal Tumor Program

Associate Professor of Oncology


Expertise: Acute Lymphoblastic Leukemia (ALL), Acute Myeloid Leukemia (AML), Aplastic Anemia, Bone Marrow Transplant, Bone Tumors, Cancer, Chronic Myeloid Leukemia (CML), Clinical Trials, Ewing's Sarcoma, Graft-versus-Host Disease, Hematologic Malignancies, Hodgkin's Disease, Leukemia, Leukemia/Lymphoma, Medical Oncology, Myelodysplastic Syndromes (MDS), Non-Hodgkin's Lymphoma (NHL), Osteosarcoma, Pediatric Oncology, Rhabdomyosarcoma, Sarcoma, Soft Tissue Sarcoma, Soft Tissue Tumors more

Research Interests: Cancer stem cells

Request an Appointment

I live in Maryland

Request an appointment through MyChart!

I live outside of Maryland

Request Appointment

I live outside of the United States

Request Appointment


The Johns Hopkins Hospital (Main Entrance)
Appointment Phone: 410-955-8751

1800 Orleans St.
The Charlotte R. Bloomberg Children's Center Building, 11th Floor
Baltimore, MD 21287 map
Phone: 410-502-7247


Undergraduate degree, BA in Biology from Johns Hopkins University in 1987. PhD from Columbia University, 1993. MD from Columbia University, 1994. Internship and Residency in Pediatrics, Johns Hopkins University 1994-1997. Fellowship in Pediatric Hematology/Oncology, Johns Hopkins University, 1997-2000. Faculty, Johns Hopkins University, 2000-present. more


  • Director of the Musculoskeletal Tumor Program
  • Associate Professor of Oncology
  • Associate Professor of Pediatrics



  • MD PhD, Columbia University College of Physicians and Surgeons (1994)


  • Johns Hopkins University School of Medicine / Pediatrics (1997)


  • Johns Hopkins University School of Medicine / Pediatric Oncology (2000)

Board Certifications

  • American Board of Pediatrics / Pediatric Hematology-Oncology (2000)

Research & Publications

Research Summary

Dr. Loeb has active laboratory and clinical research efforts. In the laboratory, Dr. Loeb studies a gene called WT1. High levels of WT1 convey a poor prognosis for patients with osteosarcoma and soft tissue sarcomas. Dr. Loebs laboratory has shown that WT1 expression is regulated, in part, by the amount of oxygen in a tumor, and that low oxygen levels lead to higher WT1 expression, which in turn leads to an increase in the ability of tumor cells to cause new blood vessels to form. The laboratory is studying both the mechanism by which oxygen levels control WT1 expression and the way WT1 regulates blood vessel growth. In a related project, Dr. Loebs laboratory is working to identify, characterize, and therapeutically target Ewing sarcoma stem cells. Cancer stem cells are thought to be inherently resistant to chemotherapy and are thought to cause most cases of refractory or relapsed disease. In collaboration with the laboratory of Dr. Jonathan Powell, Dr. Loeb has identified one pathway, called the mTOR signaling pathway, that may be important for sarcoma stem cells to resist chemotherapy. This finding prompted the initiation of a clinical trial, led by Dr. Loeb, to test the combination of Doxil, a standard chemotherapy drug, and Temsirolimus, an inhibitor of the mTOR signaling pathway, in patients with high risk sarcomas. Future clinical trials, already being planned, will test additional means by which the inherent chemoresistance of these key cells can be overcome, hopefully leading to significant improvements in the survival of patients with recurrent or refractory sarcomas.

Clinical Trial Keywords

resistance to chemotherapy, osteosarcoma, soft tissue sarcomas

Selected Publications

Savage, W.J.; DeRusso, P.A.; Resar, L.M.; Chen, A.R.; Higman, M.A.; Loeb, D.M.; Jones, R.J.; Brodsky, R.A. Treatment of hepatitis-associated aplastic anemia with high-dose cyclophosphamide. Pediatr Blood Cancer. 2007 Dec;49(7):947-951.

Loeb, D.M.; Garrett-Mayer, E.; Hobbs, R.F.; Prideaux, A.R.; Sgouros, G.; Shokek, O.; Wharam, M.D., Jr.; Scott, T.; Schwartz, C.L. Dose-finding study of 153Sm-EDTMP in patients with poor-prognosis osteosarcoma. Cancer. 2009 Jun 1;115(11):2514-2522.

Noronha, S.A.; Farrar, J.E.; Alonzo, T.A.; Gerbing, R.B.; Lacayo, N.J.; Dahl, G.V.; Ravindranath, Y.; Arceci, R.J.; Loeb, D.M. WT1 expression at diagnosis does not predict survival in pediatric AML: a report from the Children's Oncology Group. Pediatr Blood Cancer. 2009 Dec;53(6):1136-1139.

Hobbs, R.F.; Baechler, S.; Senthamizhchelvan, S.; Prideaux, A.R.; Esaias, C.E.; Reinhardt, M.; Frey, E.C.; Loeb, D.M.; Sgouros, G. A gamma camera count rate saturation correction method for whole-body planar imaging. Phys Med Biol. 2010 Feb 7;55(3):817-831.

Hobbs, R.F.; McNutt, T.; Baechler, S.; He, B.; Esaias, C.E.; Frey, E.C.; Loeb, D.M.; Wahl, R.L.; Shokek, O.; Sgouros, G. A Treatment Planning Method for Sequentially Combining Radiopharmaceutical Therapy and External Radiation Therapy. Int J Radiat Oncol Biol Phys. 2010 Oct 13.

Loeb, D.M.; Hobbs, R.F.; Okoli, A.; Chen, A.R.; Cho, S.; Srinivasan, S.; Sgouros, G.; Shokek, O.; Wharam, M.D., Jr.; Scott, T.; Schwartz, C.L. Tandem dosing of samarium-153 ethylenediamine tetramethylene phosphoric acid with stem cell support for patients with high-risk osteosarcoma. Cancer. 2010 Dec 1;116(23):5470-5478.

Schaeffer, E.M.; Loeb, S.; Walsh, P.C. The case for open radical prostatectomy. Urol Clin North Am. 2010 Feb;37(1):49-55, Table of Contents.

Activities & Honors


  • The Justin Strauss Chordoma Research Award, 2009


  • American Association for Cancer Research, Childrens Oncology Group
Is this you? Edit Profile