Characterization of Molecular Subtypes of Breast Cancer and Their Relationships With Known Breast Cancer Risk Factors Among Chinese Women in Hong Kong - A Pilot Study

Background: Breast cancer incidence is increasing rapidly among many Asian populations primarily due to the adaptation of a Westernized lifestyle. However, Asian women seem to have a distinctive profile of breast cancer that differs from that seen in Western populations, such as earlier age at onset, more advanced stage, and higher frequency of ER-negative tumors. The disproportionally high rates among younger women were also seen among U.S.-born Asian women, such as Chinese, Filipina, Indian, and Pakistani women. These findings suggest that Asian breast cancer may have a distinct etiology that is not fully explained by adapting a westernized lifestyle. Recent molecular studies have suggested that breast cancers comprise several biologically and clinically distinct tumor subtypes. Epidemiologic evidence suggests that associations with breast cancer risk factors may vary by tumor subtype. However, most previous studies were conducted in Western populations; large, population-based epidemiologic studies characterizing molecular subtypes of breast cancer in Asian women are limited. In this study, we would like to characterize the molecular profile of breast cancer among Chinese women in Hong Kong and associate the molecular features with clinical and etiologic factors. An improved understanding of the inter-relationships among age, breast cancer subtypes, and race/ethnicity is critical for the development of targeted prevention and the best and most efficacious therapy.

Objectives: To assess the technical feasibility of 1) collecting fresh frozen tissues and fixed tissue blocks from breast cancer cases in Hong Kong, and 2) conducting tumor profiling analyses in the collected tissues.

Eligibility: Breast cancer cases who are participants in an ongoing breast cancer case control study among Hong Kong women (Night shift and breast cancer: a case-control study among Hong Kong women, led by Dr. Tse at Chinese University in Hong Kong) and who will receive surgery at the North District Hospital, HK, in 2013.

Design: In this feasibility study, we plan to collect fresh frozen and fixed tissues (tumor and adjacent normal) from approximately 100 breast cancer cases who have given consent to participate in our breast tissue collection pilot study. DNA and RNA will be extracted from frozen tumors and assessed for quality and yield. We will then conduct expression profiling analysis in a subset of cases (N approximately 10) to determine the quality of RNA in molecular profiling analysis. We will also determine whether there are enough epithelial benign and tumor tissues for the construction of tissue microarrays (TMAs). The results from this feasibility study will inform our decision on whether or not to pursue a large scale study.