Genetics of Mammographic Appearances and Patterns (The GenMap Study)

Trial Information

Genetics of Mammographic Appearances and Patterns (The GenMap Study)

High mammographic density (HMD) is the strongest risk factor for non-familial breast cancer
apart from age and gender. Studies of sisters and twins suggest that approximately 67% of
the variation in density is attributable to common genetic factors. However, to date,
efforts to identify genetic determinants of HMD have achieved limited success. We and others
(Boyd et al Lancet Oncol 2009) postulate that this lack of progress in identifying genetic
determinants of density is related to a failure to study younger women and misclassification
of density. As women age, their breast tissues undergo atrophy, which is manifested
radiologically as a decrease in mammographic density, resulting in a convergence of density
values and a masking of inter-person variation. This protocol is intended to demonstrate
the feasibility of methods that we plan to use in a full-scale analysis of mammographic
density among women under age 50 years who receive care at the University of Vermont,
Fletcher Allen Health Care (FAHC) and have been followed through the Vermont Breast Cancer
Surveillance System (VBCSS).

The study capitalizes on infrastructure that has been established through the BREAST Stamp
project that is being carried out in two phases: phase one is a feasibility study:
specifically, we propose to demonstrate that we can use a mailing to collect
Oragene(Registered Trademark) tube format saliva collection kits as a source of germline DNA
and a short self-administered questionnaire. We have completed the phase one feasibility
portion of the protocol, which targeted 200 women by mail. As of January 25, 2011, of the
200 that were mailed invitations, 195 women were contacted (5 subjects forms were returned
because of bad addresses), and 106 women enrolled. We are currently analyzing data from
this feasibility study to determine participation rates, quality of completed questionnaires
and saliva samples, and frequencies and distributions of key risk factors and demographics
of participants. This collection of specimens and data will be used to inform the launch of
phase two, the full-scale study to identify determinants of mammographic volumetric density
among 10,000 women less than 50 years of age for whom raw images and density data are
already collected.