Temporal trends in incidence and mortality of molecular subtypes of breast cancer to inform public health, policy and prevention (360G-Wellcome-207800_Z_17_Z)

Numerous molecular markers have been identified to have treatment and prognostic value for breast cancer, but their distribution across populations and potential translation into cancer prevention or clinical interventions remains to be determined. Oestrogen receptor (ER) expression in tumours is a marker of aetiologic and treatment differences, and preliminary data from over 73,000 cases in Scotland, show ER-positive breast cancers rising and ER- negative breast cancers declining from 1997-2014. The underlying reasons for these divergent trends are lacking as are whether important subgroups of the population differ in these trends (e.g. age, socio-economic status, and screening). Further, recent advances in 'omics technologies have changed breast cancer treatment regimens beyond ER, identifying subgroups of cases that might benefit from different chemotherapy, radiotherapy and hormonal treatment regimens. Using the electronic medical record datasets of Scotland we seek to develop a high-dimensional 'omics dataset through a proof-of- principle study using 1600 Lothian Bioresource stored tissues from two five- year periods. This proposal will quantify at the population level how many women might benefit from new 'omics defined molecular subtypes of breast cancer, with the goal of defining the populations that might most benefit from prevention, screening or treatment interventions in the UK and abroad.