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Lester and Sue Smith Breast Center

Houston, Texas

The Lester and Sue Smith Breast Center's mission is to improve prevention, diagnosis and treatment of breast disease.
Lester & Sue Smith Breast Center
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Michael T. Lewis, Ph.D. - Biography

Michael T. Lewis, Ph.D.Assistant Professor

Phone: 713-798-3296
Fax: 713-798-1659

Lewis Lab Web Site


1982-1986 - B.S. Biology, College of William and Mary
1989-1995 - Ph.D. Biology, University of California
1995-1998 - Post-doc. Biology, University of California
1999 - Post-doc. Physiology and Biophysics, University of Colorado

Research Interest:

The Lewis Laboratory studies the developmental biology of the mammary gland as it relates to both normal breast function and breast cancer progression. Current laboratory research is centered on the role of hedgehog signal transduction in mammary gland development and breast cancer using the mouse as a model organism.

During embryonic development, the hedgehog signal transduction network mediates cell-cell communication and is required for normal organ formation. However, genetic mutation of hedgehog network genes can cause severe birth defects, basal cell carcinoma of the skin, and other tumors including lethal medulloblastomas of the brain.

Our work has demonstrated that loss-of-function mutations in two hedgehog network genes, Patched-1 (Ptc-1) and Gli-2, cause cancer-like lesions that closely resemble human ductal carcinoma in situ (DCIS). More recently, hedgehog signaling has been found to be required for functional differentiation of the gland at the onset of lactation.

The specific mechanism by which mutations in the hedgehog network lead to differentiation failure and mammary lesions is not known. Our data lead us to ask several fundamental questions, among which are:

  1. Which genes in the hedgehog signaling network are required for different phases of mammary gland development.
  2. In which tissue compartment(s) do these genes function?
  3. What genes regulate, or are regulated by hedgehog signaling?
  4. How does the hedgehog network interact with other hormone- and growth factor-dependent regulatory networks (e.g. estrogen, progesterone and TGFß-1)?
  5. Do hedgehog signaling disruptions lead to neoplasia in the human breast?

Professional Activities, Awards and Honors:

1989 University of California Regents Fellowship
1992 - Present Charter member - Sigma Xi ( Santa Cruz chapter)
1996 University of California Breast Cancer Research Program Postdoctoral Research Award 2000 Department of Defense IDEA Award
2001 Organizer – Gordon Research Conference in Mammary Gland Biology Workshops 2001-2002 Member - Pathogenesis Study Section – Univ. California Breast Cancer Research Program
2001-Present Member - San Antonio Breast Cancer Symposium Organization Committee 2003 Organizer – NIH Workshop on Homeobox genes in mammary gland development
2003-Present Member - Tumor Progression Study Section – Univ. California Breast Cancer Research Program
2003-Present Member – Molecular Biology Genetics 2 Study Section - Dept. Defense Breast Cancer Research Program
2003 Susan Love M.D. Breast Cancer Research Foundation Grant Award
2003 Department of Defense CONCEPT Award

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