Principal Investigator

Isaac Brownell, M.D., Ph.D.

A board-certified dermatologist, Dr. Isaac Brownell is an attending physician on the NIH Clinical Center’s Dermatology Consultation Service and co-directs the Cutaneous Oncology Program at the Walter Reed National Military Medical Center. 

The Cutaneous Development and Carcinogenesis Section studies the signaling pathways such as Hedgehog signaling that regulate the development and maintenance of normal skin, and the changes in these signals that occur during the formation of skin cancer. Our investigations include studying the specification and maintenance of cell lineages in the skin, as well as studying the regulation of stem cells in the skin, and using mouse genetics to model carcinogenesis in the skin.

A current focus in the lab is investigating the the neuro-cutaneous interface and the regulation of neuroendocrine cells (Merkel cells) in the skin. We are also analyzing Merkel cell carcinomas, and are developing pre-clinical mouse models for this uncommon but aggressive skin cancer.

Ongoing Clinical Trials


Adjunct Investigator, National Cancer Institute (NCI)
Postbac Fellow
Lab Manager
Visiting Fellow
Research Fellow
Postbac Fellow
Visiting Fellow

Image & Media Gallery

Scientific Publications

Hedgehog signaling inhibitors fail to reduce Merkel cell carcinoma viability. Carroll TM, Williams JS, Daily K, Rogers T, Gelb T, Coxon A, Wang SQ, Crago AM, Busam KJ, Brownell I.

Avelumab in patients with chemotherapy-refractory metastatic Merkel cell carcinoma: a multicentre, single-group, open-label, phase 2 trial.  Kaufman HL, Russell J, Hamid O, Bhatia S, Terheyden P, D'Angelo SP, Shih KC, Lebbé C, Linette GP, Milella M, Brownell I, Lewis KD, Lorch JH, Chin K, Mahnke L, von Heydebreck A, Cuillerot JM, Nghiem P.

A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development.  Xiao Y, Thoresen DT, Miao L, Williams JS, Wang C, Atit RP, Wong SY, Brownell I.

Evaluating blood levels of neuron specific enolase, chromogranin A, and circulating tumor cells as Merkel cell carcinoma biomarkers.  Gaiser MR, Daily K, Hoffmann J, Brune M, Enk A, Brownell I.

Neural Hedgehog signaling maintains stem cell renewal in the sensory touch dome epithelium.  Xiao Y, Thoresen DT, Williams JS, Wang C, Perna J, Petrova R, Brownell I.

Nerve-derived sonic hedgehog defines a niche for hair follicle stem cells capable of becoming epidermal stem cells.  Brownell I, Guevara E, Bai CB, Loomis CA, Joyner AL.

Last Updated: November 2018