What are the new ideas about how chemicals cause cancer, and how should we think about risk?


Welcome: Setting the stage for an exploration of cancer and environment.


  • Kate Z. Guyton, PhD - National Academies of Sciences, Engineering, and Medicine
    • Key characteristics of carcinogens. What are the tools we have now to identify carcinogens, including chemicals not considered to be “complete carcinogens” that may contribute to cancer? Slides
  • Mary Beth Terry, PhD - Columbia University, Mailman School of Public Health and Irving Cancer Center
    • Precision Prevention: Gene X Environment Interactions: PAHs and the Breast Cancer Family Cohort. Slides

Panel: How do chemically induced cancers appear in the clinic? A “case study” of the Wilmington, Massachusetts childhood cancer cluster.

Moderator: Richard Clapp, ScD - First Director of the Massachusetts Cancer Registry and Professor Emeritus at Boston University School of Public Health.

  • Brian Dellascio, Wilmington childhood cancer survivor and patient advocate
  • Kathleen Barry, DPT, Wilmington community liaison and advocate
  • Marc Nascarella, MS, PhD, CPH, Chief Toxicologist, MDPH Bureau of Environmental Health Branch, leader of a recent survey-based study about Clinicians’ Experience with Environmental Exposures


In Session 1, Dr. Kate Guyton spoke about the multiple streams of evidence—including experimental studies in animals and cells as well as observational epidemiology--used by the International Agency for Research on Cancer (IARC) to categorize chemicals as known or suspected carcinogens.  She also spoke about the “key characteristics of carcinogens” approach to cancer causation, which recognizes that carcinogens can impact one or more biological pathways, including damage to DNA, hormone disruption, suppressing immune function, and other processes.

Dr. Mary-Beth Terry addressed the topic of gene environment interactions, noting that rising cancer incidence in people under age 50 cannot be due to genetic changes alone.  Dr. Terry highlighted her research on exposures to polycyclic aromatic hydrocarbons, or PAHs, in air pollution, grilled and smoked food, etc. Her work demonstrates the importance of studying sub-populations—for example, people exposed during particular windows of vulnerability, like prenatally or during puberty, or women with genetic susceptibility to breast cancer.  These women show much greater risk of breast cancer from PAHs than a more heterogeneous population of women with breast cancer.   

We then heard from stakeholders involved with the Wilmington Childhood Cancer cluster about their roles in working with public health officials to identify and investigate an unusual occurrence of cancers in their community during the 1990s.   A study recently released by the Massachusetts Department of Public Health strongly suggests associations between the development of childhood cancers and maternal exposure to carcinogenic compounds which had contaminated the Wilmington public water supply, and vindicated the concerns raised by the affected families. The panel raised the question: what might have been done sooner to eliminate the exposures that caused these cancers?  

Additional Materials

Session 1 recording

Q&A and resources


Forum Overview

Session 2

Session 3