Dr. Alan Meeker is an Assistant Professor of Pathology, Oncology, Urology at the Johns Hopkins School of Medicine, as well as Biochemistry and Molecular Biology at the Johns Hopkins Bloomberg School of Public Health. Dr. Meeker co-directs the Histology, Immunohistochemistry, and slide scanning services in the Laboratory of Johns Hopkins Oncology Tissue and Imaging Services, and serves on the faculty of the Graduate Programs in Pathobiology, Cellular and Molecular Medicine, and Biochemistry and Molecular Biology. He joined the Hopkins faculty in 2006.
Dr. Meeker has spent his career studying cancer. His main research focus has been on chromosomal structures located at all chromosomal termini called, "telomeres." Telomeres have the unique property that they shorten each time a cell divides. This serves as the counting mechanism for a cell division clock, and if telomeres shorten significantly this will cause the cells possessing them to cease any further cell division; a process believed to be a protective mechanism for the prevention of cancer, a disease due in large part to uncontrolled cell division. However, in rare instances this protective barrier fails (e.g. due to random mutation), allowing cell populations to continue to divide, one consequence of which being very short telomeres. Such telomeres that are too short appear to contribute to the genetic instability, which is a major contributor to both cancer initiation and progression to more aggressive cancer behavior (e.g. metastatic spread). Telomeres are also believed to be related to human aging and the age-related phenomenon of cellular senescence; limiting cell division and thus impairing important activities, such as wound healing.
Dr. Meeker's primary studies on the relationship between shortened telomeres and cancer have mainly involved prostate, breast, pancreatic, and brain cancers. He was part of a Johns Hopkins team that developed a new quantitative fluorescence microscopy technique to measure telomere lengths directly in archival human tissues. In order for cancers to survive and advance, they must find a way to stop their telomeres from continuing to shorten so far that they become lethal to the cancer cells. Most cancers do this by abnormally activating a gene called telomerase that can counter-balance the telomere losses by synthesizing new telomere DNE on the ends of the chromosomes. Dr. Meeker's lab has also focused on the small but significant set of cancers that somehow maintain their telomeres without telomerase, so-called Alternative Lengthening of Telomeres cancers, or "ALT."
The overall goal of these studies is to better understand telomere biology in cancer, thus providing new therapeutic targets to effectively treat this devastating disease.
In addition to the many academic papers he has published, Dr. Meeker also contributed chapters to the books Prostate Cancer: Biology, Genetics, and the New Therapeutics as well as Campbell-Walsh Urology, 10th and 11th ed.