Dr. John's research focus has been on the epidemiology of breast, prostate, and ovarian cancer, particularly in Hispanic and African-American populations. Since joining NCCC, Dr. John has established several large population-based resources to study the etiology of these cancers, with emphasis on the role of lifestyle factors that are potentially modifiable, genetic susceptibility, the combined effects of environmental and genetic factors, and racial/ethnic differences in risk factors that contribute to racial/ethnic disparities in the incidence of these cancers.

BREAST CANCER: Dr. John has conducted a series of population-based case-control studies of breast cancer, the San Francisco Bay Area Breast Cancer Study, in nearly 5,000 Hispanic, African-American and non-Hispanic white women. Extensive interview data were collected on a wide range of hormonal and lifestyle factors, as well as blood samples for studies of genetic susceptibility factors and gene-environment interactions. Major areas of interest concern the role of physical activity, body size and weight gain; vitamin D from sun exposure, diet and supplements, a topic that has gained major prominence in recent years; heterocyclic amines associated with cooking methods; and early-life exposures. Collaborative molecular studies have focused on the role of genetic admixture, polymorphisms in the vitamin D receptor (VDR) gene, obesity-related and fat-metabolizing genes, and gene-environment interactions. The Hispanic component of this resource is one of the largest case-control studies of breast cancer conducted in Hispanic women living in the U.S. Dr. John is interested in gaining a better understanding of changes in lifestyle factors that follow migration to the U.S. and subsequent acculturation and their impact on the occurrence of breast cancer in subsequent generations. Efforts are underway to study survival in relation to lifestyle and other factors among the over 2,200 breast cancer cases included in this study.

PROSTATE CANCER: A second major focus of Dr. John's work has been the etiology of prostate cancer which remains largely unknown. Most recently, she has conducted a population-based case-control study of advanced prostate cancer in conjunction with a similar study conducted in Southern California by Dr. Sue Ingles at the University of Southern California. This two-center study, the California Collaborative Study of Advanced Prostate Cancer, serves as a rich resource to elucidate the etiology of advanced prostate cancer in African-American, Hispanic and non-Hispanic white men. Current investigations focus on the role of vitamin D, physical activity, body size, diet, heterocyclic amines and genetic susceptibility factors. Dr. John is also participating in several large international consortia that seek to identify new susceptibility genes through admixture mapping and genome-wide association studies.

CANCER FAMILY REGISTRIES: In collaboration with researchers at Stanford University, Dr. John has been involved in the establishment of two family registries to study the genetic epidemiology of breast and ovarian cancer. She is Principal Investigator of the Northern California site of the Breast Cancer Family Registry, an international consortium established by the National Cancer Institute in 1995 for interdisciplinary and translational studies of the genetic epidemiology of breast cancer. The six collaborating family registries in the U.S., Canada and Australia have enrolled over 13,000 breast cancer families, with over 3,000 families from the San Francisco Bay area. Dr. John is involved in numerous international collaborations that use these resources, including studies of BRCA1 and BRCA2 mutations in minority populations, modifying effects of lifestyle factors in BRCA1 and BRCA2 mutation carriers, other susceptibility genes such as ATM and CHK2, and the genetics of mammographic density, a major risk factor for breast cancer.

• Garner CP, Ding YC, John EM, Ingles SA, Olopade OI, Huo D, Adebamowo C, Ogundiran T, Neuhausen SL "Genetic variation in IGFBP2 and IGFBP5 is associated with breast cancer in populations of African descent." Hum Genet 2008; More
• Setiawan VW, Chu LH, John EM, Ding YC, Ingles SA, Bernstein L, Press MF, Ursin G, Haiman CA, Neuhausen SL "Mitochondrial DNA G10398A variant is not associated with breast cancer in African-American women." Cancer Genet Cytogenet 2008; 181: 1: 16-9 More
• John EM, Schwartz GG, Koo J, Wang W, Ingles SA "Sun Exposure, Vitamin D Receptor Gene Polymorphisms, and Breast Cancer Risk in a Multiethnic Population." Am J Epidemiol 2007; More
• John EM, Miron A, Gong G, Phipps AI, Felberg A, Li FP, West DW, Whittemore AS "Prevalence of pathogenic BRCA1 mutation carriers in 5 US racial/ethnic groups." JAMA 2007; 298: 24: 2869-76 More
• Haiman CA, Setiawan VW, Xia LY, Le Marchand L, Ingles SA, Ursin G, Press MF, Bernstein L, John EM, Henderson BE "A variant in the cytochrome p450 oxidoreductase gene is associated with breast cancer risk in african americans." Cancer Res 2007; 67: 8: 3565-8 More