Biography
Dr. Morton received a B.A. from Dartmouth College and a Ph.D. in Epidemiology from Yale University with a focus on cancer epidemiology. She then joined DCEG’s Hormonal and Reproductive Epidemiology Branch as a Postdoctoral Fellow and became a Research Fellow. During her doctoral and postdoctoral training concentrated in molecular epidemiology, she focused her research on understanding the causes of lymphoid neoplasms.
In 2008, Dr. Morton joined the Radiation Epidemiology Branch (REB) as a tenure-track investigator. She expanded her research to the study of multiple primary cancers, evaluating the carcinogenic effects of radiotherapy and chemotherapy, as well as other environmental and genetic risk factors for second cancers. Dr. Morton has been recognized for her research contributions with the NCI Career Development Innovation Award, the NIH Fellows Award for Research Excellence, and the Lymphoma Foundation of America’s Young Scientist Award.
Research Interests
Second cancers
In recent decades, new treatments and early detection have dramatically improved cancer survival. However, second cancers are a leading cause of morbidity and mortality among survivors. In 2003, REB investigators, together with international collaborators, launched a multi-center study of gastrointestinal (GI) cancers (stomach, pancreas, esophagus) among survivors of Hodgkin lymphoma and cancers of the testis, breast, and cervix. Dr. Morton now serves as the Principal Investigator for the study.
The initiative is made up of seven case-control studies of over 800 cases and 1500 controls. Investigators abstracted detailed treatment information from medical records, and estimated radiation doses to the GI organs with individualized radiation dosimetry. The study represents the first comprehensive effort beyond the atomic bomb survivor studies to quantify the radiation dose-response relationship for upper-GI cancers, and it is one of few studies to quantify chemotherapy-related solid tumor risks. The study also includes four international population-based cohorts including over 900,000 1-year survivors of Hodgkin lymphoma and cancers of the testis, breast, and cervix for site-specific second cancer incidence and trends in cause-specific mortality. From analyses of these cohorts researchers have newly quantified the age and temporal patterns of risk for subsequent cancer and non-cancer outcomes. In addition, they have noted that excess risks often persist 25 years or more following the first cancer diagnosis.
Treatment-related myelodysplasia and leukemia is a rare but highly fatal complication of radiotherapy and cytotoxic chemotherapy that appears in the years immediately following treatment. Expanding on her expertise and long-standing interest in hematopoietic malignancies, Dr. Morton is investigating the feasibility of launching a new research project investigating leukemia risks associated with current treatments and genetic susceptibility.
Although treatments for first primary cancer are an important cause of subsequent malignancy, many second cancers are likely caused by shared environmental and genetic risk factors. Historically, studies of second cancers have relied on historical medical records, with limited information on additional risk factors. Dr. Morton and collaborators are developing novel strategies for studying second cancers. For example, they are pilot testing an effort to pool data from existing epidemiologic cohort studies to evaluate second cancer risks associated with lifestyle, environmental, and genetic factors.
Etiology of lymphoid neoplasms
Non-Hodgkin lymphoma (NHL), the sixth most common cancer in the United States, comprises a group of closely related yet heterogeneous diseases. Because understanding differences in risk among NHL subtypes may illuminate mechanisms of lymphomagenesis, Dr. Morton’s research is focused on investigating environmental and genetic risk factors for lymphoma by disease subtype.
The International Lymphoma Epidemiology Consortium (InterLymph), initiated in 2001, comprises international investigators who have completed or are conducting ongoing case-control studies of NHL. Dr. Morton led the InterLymph Pathology Working Group efforts to develop a nested classification of lymphoid neoplasms for epidemiologic research. This classification has been adopted by InterLymph, numerous case-control and cohort studies, and the SEER Cancer Statistics Review. Dr. Morton is now leading a consortium-wide effort to comprehensively understand patterns of numerous risk factors across both common and rare NHL subtypes. She also collaborates on a number of other InterLymph projects, including an ongoing genome-wide association study to identify genetic susceptibility to NHL.
In addition to InterLymph, Dr. Morton is also collaborating on a number of studies of patients with HIV/AIDS or who received a solid organ transplant, since individuals with severe immunosuppression have strikingly increased risk for hematologic malignancies.
Keywords
Second cancers; neoplasms, radiation-induced; non-Hodgkin lymphoma; leukemia; genetic susceptibility.
Selected Publications
- Morton LM, Chanock SJ. A step towards slaying the hydra of second cancers. Nat Med 2011;17:924–5.
- Morton LM, Curtis RE, Linet MS, Bluhm EC, Tucker MA, Caporaso N, Ries LAG, Fraumeni Jr. JF. Second cancer risks following non-Hodgkin lymphoma and chronic lymphocytic leukemia: differences by lymphoma subtype. J Clin Oncol 2010;28:4935-44.
- Turner JJ, Morton LM, Linet MS, Clarke CA, Kadin ME, Vajdic CM, Monnereau A, Maynadié M, Chiu BC, Marcos-Gragera R, Costantini AS, Cerhan JR, Weisenburger DD. InterLymph hierarchical classification of lymphoid neoplasms for epidemiologic research based on the WHO Classification (2008): update and future directions. Blood 2010;116:e90-8.
- Morton LM, Purdue MP, Zheng T, Wang SS, Armstrong B, Zhang Y, Menashe I, Chatterjee N, Davis S, Lan Q, Vajdic CM, Severson RK, Holford TR, Kricker A, Cerhan JR, Leaderer B, Grulich AE, Yeager M, Cozen W, Zahm SH, Chanock SJ, Rothman N, Hartge P. Risk of non-Hodgkin lymphoma associated with germline variation in genes that regulate the cell cycle, apoptosis, and lymphocyte development. Cancer Epidemiol Biomarkers Prev 2009;18:1259-70.
- Morton LM, Wang SS, Cozen W, Linet MS, Chatterjee N, Davis S, Severson RK, Colt JS, Vasef MA, Rothman N, Blair A, Bernstein L, Cross AJ, De Roos AJ, Engels EA, Hein DW, Hill DA, Kelemen LE, Lim U, Lynch CF, Schenk M, Wacholder S, Ward M, Zahm SH, Chanock SJ, Cerhan JR, Hartge P. Etiologic heterogeneity among non-Hodgkin lymphoma subtypes. Blood 2008;112:5150-60.
- Morton LM, Wang SS, Devesa SS, Hartge P, Weisenburger DD, Linet MS. Lymphoma incidence patterns by WHO subtype in the United States, 1992-2001. Blood 2006;107:265-76.
Collaborators
DCEG Collaborators
- Amy Berrington de Gonzalez, Neil E. Caporaso, Stephen J. Chanock, Nilanjan Chatterjee, Rochelle E. Curtis, Susan S. Devesa, Eric A. Engels, Todd Gibson, Ethel S. Gilbert, Patricia Hartge, Clara J. Kim, Ruth A. Kleinerman, Qing Lan, Martha S. Linet, Mark Purdue, Preetha Rajaraman, Nathaniel Rothman, Josh Sampson, Meredith Shiels, Peggy Tucker, Sholom Wacholder, Shelia H. Zahm.
Other NCI Collaborators
- Ola Landgren, M.D., Ph.D., Multiple Myeloma Section, Center for Cancer Research
- Louis M. Staudt, M.D., Ph.D., Metabolism Branch, Center for Cancer Research
Other Scientific Collaborators
- James R. Cerhan, M.D., Ph.D., Mayo Clinic College of Medicine, Rochester, MN
- Christina A. Clarke, Ph.D., Cancer Prevention Institute of California, Duarte, CA
- Wendy Cozen, D.O., M.P.H., University of Southern California, Los Angeles, CA
- Scott Davis, Ph.D., M.S., Fred Hutchinson Cancer Research Center, University of
- Washington, Seattle, WA
- Graca M. Dores, M.D., MP.H., VA Medical Center, Oklahoma, OK
- Eric J. Holowaty, M.D., F.R.C.P.C., M.Sc., Cancer Care Ontario, Toronto, Ontario, Canada
- Heikki Joensuu, M.D., Ph.D., Helsinki University Central Hospital, Helsinki, Finland
- Froydis Langmark, M.D., Cancer Registry of Norway, Oslo, Norway
- Charles F. Lynch, M.D., M.S., Ph.D., University of Iowa, Iowa City, IA
- Kenan Onel, M.D., Ph.D., University of Chicago, Chicago, IL
- Richard K. Severson, Ph.D., Karmanos Cancer Institute, Wayne State University, Detroit, MI
- Susan Slager, Ph.D., Mayo Clinic College of Medicine, Rochester, MN
- Hans H. Storm, M.D., Danish Cancer Society, Copenhagen, Denmark
- Marilyn Stovall, Ph.D., University of Texas M.D. Anderson Cancer Center, Houston, TX
- Sophia S. Wang, Ph.D., City of Hope National Medical Center, Los Angeles, CA
- Dennis D. Weisenburger, M.D., University of Nebraska, Omaha, NE