Israeli and Palestinian Researchers Cooperate to Find Risk Factors for B
Cell Non-Hodgkin Lymphoma
In both groups, recreational sun exposure, black hair-dye use, a history of
hospitalization for infection, and having a first-degree relative with a
blood cancer were associated with B-NHL. Each group had unique risk factors
The Hebrew University of Jerusalem – Jerusalem, February 20, 2017 —
Non-Hodgkin lymphomas (NHL), tumors which may originate from B or T
lymphocytes, account for approximately 3% of the worldwide cancer burden.
Most epidemiological studies of NHL have been carried out in North American
and European populations, with a few focusing on East Asian populations.
Very few epidemiological studies have been conducted on B-cell non-Hodgkin
lymphoma (B-NHL) in Middle Eastern populations.
Since Israelis and Palestinians represent genetically and culturally diverse
populations living in geographic proximity, research analyzing their risk
factors can enrich our understanding of genes and environment in the
causation of lymphoma. Despite sharing the same ecosystem, the populations
differ in terms of lifestyle, health behaviors and medical systems. Yet both
populations report high incidences of NHL, which represents the fifth most
common malignancy in Israel and the eighth most common malignancy among West
Bank Palestinians. (As of 2012, Israel also ranked first in the world in NHL
Now, Israeli and Palestinian researchers, led by Prof. Ora Paltiel, Director
of the Hebrew University-Hadassah Braun School of Public Health and
Community Medicine, and a Senior Physician in Hadassah’s Hematology
Department, have conducted a large scale epidemiological study examining
risk factors for B-NHL and its subtypes in these two populations.
Recruiting from both the Palestinian Arab and Israeli Jewish populations,
the researchers looked at medical history, environmental and lifestyle
factors among 823 people with B-cell non-Hodgkin lymphoma (B-NHL) and 808
healthy controls. Using data from questionnaires, pathology review, serology
and genotyping, they uncovered some risk factors common to both populations
and other factors unique to each population.
The data, reported in the peer-reviewed journal PLOS ONE, showed that in
both populations, overall B-NHL was associated with recreational sun
exposure, black hair-dye use, a history of hospitalization for infection,
and having a first-degree relative with a blood cancer. An inverse
association was noted with alcohol use. Some exposures, including smoking
and greater-than-monthly indoor pesticide use, were associated with specific
subtypes of B-NHL.
The data also pointed to differences between the populations. Among
Palestinian Arabs only, risk factors included gardening and a history of
herpes, mononucleosis, rubella, or blood transfusion, while these factors
were not identified in the Israeli Jewish population. In contrast, risk
factors that applied to Israeli Jews only included growing fruits and
vegetables, and self-reported autoimmune diseases.
The researchers concluded that differences in the observed risk factors by
ethnicity could reflect differences in lifestyle, medical systems, and
reporting patterns, while variations by lymphoma subtypes infer specific
causal factors for different types of the disease. These findings require
further investigation as to their mechanisms.
The fact that risk factors operate differently in different ethnic groups
raises the possibility of gene-environment interactions, that is, that
environmental exposures act differently in individuals of different genetic
backgrounds. But this divergence may reflect differences in diet, cultural
habits, socioeconomic, environmental and housing conditions, medical
services, exposure to infections in early life or other factors.
This study reflects a unique joint scientific effort involving Israeli and
Palestinian investigators, and demonstrates the importance of cooperative
research even in politically uncertain climates. Cancer epidemiology will be
enriched through the broadening of analytic research to include
under-studied populations from a variety of ethnicities and geographic
“Apart from the scientific contribution that this research provides in terms
of understanding risk factors for NHL, the study entails an important
research cooperation among many institutions. The study provided
opportunities for training Palestinian and Israeli researchers, and will
provide for intellectual interaction for years to come. The data collected
will also provide a research platform for the future study of lymphoma.
Epidemiologic research has the potential to improve and preserve human
health, and it can also serve as a bridge to dialogue among nations,” said
Prof. Ora Paltiel, Director of the Hebrew University-Hadassah Braun School
of Public Health and Community Medicine, and a Senior Physician in
Hadassah’s Hematology Department.
Participating institutions in this research included: Braun School of
Public Health and Community Medicine, and Depts. of Hematology and
Pathology, Hadassah-Hebrew University Medical Center; Dept. of Medical
Laboratory Sciences and Dept. of Community Medicine, Faculty of Medicine,
Al Quds University; Cancer Care Center, Augusta Victoria Hospital; Beit
Jalla Hospital; Department of Statistics, Hebrew University; Department of
Primary Health Care, Palestinian Ministry of Health; Tisch Cancer Institute
and Institute for Translational Epidemiology, Mount Sinai School of
Medicine; Rambam Medical Center and Rappaport Faculty of Medicine, Technion;
Chaim Sheba Medical Center and Meir Medical Center and Tel Aviv University.
FUNDING: This study was supported by the MERC/USAID grant
#TA-MOU-11-M31-025; by the Israel Science Foundation (ISF) grant #877/10;
and by the Hadassah University Hospital Compensatory Fund.
CITATION: Ethnic Variation in Medical and Lifestyle Risk Factors for B cell
non-Hodgkin Lymphoma: A Case-Control Study among Israelis and Palestinians.
Geffen Kleinstern, Rania Abu Seir, Riki Perlman, Areej Khatib, Ziad Abdeen,
Husein Elyan, Ronit Nirel, Gail Amir, Asad Ramlawi, Fouad Sabatin, Paolo
Boffetta, Eldad J. Dann, Meirav Kedmi, Martin Ellis, Arnon Nagler, Dina Ben
Yehuda, Ora Paltiel. PLoS ONE 12(2): e0171709.