Josh Neman

Assistant Professor
Neurosurgery
Keck School of Medicine, USC/Norris Comprehensive Cancer Center

Research Topics

  • Neuroscience
  • Tumor microenvironment
  • Pediatric Brain Tumors
  • Breast Cancer
  • Brain Tumors
  • Metastasis

Research Overview

As a neuroscientist, Dr. Neman’s aim is to raise awareness that transdisciplinary research between neurobiology and cancer foundations can advance our current understanding of how the nervous system contributes to primary and metastatic brain tumors. By leveraging current advances in neurodevelopment and the brain’s microenvironment, we can uncover novel mechanism used by the nervous system to promote tumor growth and spread. This will ultimately result in development of improved strategies for cancer prevention and treatment of patients with these devastating disease.

Research on Breast to Brain Metastasis
While most people are aware of primary breast cancer, many forget that it is the metastasis that is the patient’s ultimate malice. Breast cancer metastasizes to the brain in approximately 30-40% of patients with either triple negative or Her2+ subtype. 90% of patients with these breast cancer subtypes will die of metastasis to the brain. While targeted therapies have improved management of the disease outside of the brain, poor bioavailability to the brain increases its potential as a sanctuary site for metastatic disease.

Metastasis is the result of successful interplay between tumor cells and newly encountered microenvironments. After crossing the brain’s protective gateway (blood-brain-barrier), disseminated breast cancer cells arrive in a dynamic cellular and molecular landscape that presents unique selection pressures. Much of what we know about the brain’s microenvironment comes from the field of neurobiology. Thus, as neuroscientists, our approach is to study breast cancer and its ultimate metastasis to the brain from the perspective of the brain.

Research on Pediatric Medulloblastomas
Brain tumors are the most common cause of childhood oncological death. Furthermore, medulloblastomas (MBLs), originating in the cerebellum, are most common malignant pediatric brain tumors. MBL therapy includes surgical resection, aggressive chemotherapy, and usually also irradiation, but high risk patients continue to have poor survival. Moreover, survivors are often left with significant neurological, intellectual, and physical disabilities.

Recent evidence suggests that MBLs comprises at least 4 molecularly distinct subgroups (WNT, SHH, Group 3 and Group 4) which differ clinically and molecularly. It is currently thought that most MBL arise from cerebellar granule neuron precursor cells (cGNPs), which reside in the external granular layer (EGL) that transiently lines the outer surface of the fetal/perinatal cerebellum. The transcription factors, MYC and MYCN, are overexpressed in many MBLs. MBL show increased levels of the GABAergic receptor with dependence on this receptor for growth. However, the role of the MBL adaptation to its cerebellar microenvironment is only scantly understood. Therefore, our goal is to elucidate the tumor microenvironment in these pediatric brain tumors and develop an effective treatment for childhood with medulloblastomas.