Abstract P2-10-15: Different MammaPrint and BluePrint molecular profiles and clinical-pathological features of early stage breast cancer in Chinese patients in the United States and Hong Kong
Authors: Kwong Ava , Untch Sarah , Kling Heather M. , Finn Christine , Audeh William , Shin Vivian , Ishtihar Sherene , Chen Margaret 
Published: March 2020

Background: Breast cancer rates among Asian women are relatively low compared with Western populations; however, rates have increased in recent years, and it is the most common cancer in women. Few studies have characterized clinical-pathological features and molecular subtypes in Asian breast cancer patients, although substantial variation in occurrence among Asian subpopulations has been reported. Here, we report clinical factors, pathology, and molecular profiles of Chinese patients enrolled in the US and Hong Kong, HKSAR, and from age-matched Caucasian (Cau) and African-American (AA) patients.

Methods: This analysis included Chinese patients enrolled in the United States (n=24) and Hong Kong (n=42) with early stage, invasive breast cancer for whom clinical characteristics were captured with informed consent, enrolled between 2013 and 2018 (NCT02669745). For ethnicity comparisons, age-matched Cau (n=132) and AA (n=33) patients were included from the prospective, US-based FLEX registry (NCT03053193). Ethnicity was patient reported. Clinical characteristics, pathology, and results from the 70-gene (70-GS, MammaPrint) risk of recurrence and 80-gene (80-GS, BluePrint) molecular subtyping signatures were compared.

Results: The median age at diagnosis for Chinese was 51 years, and patients were 53.8% pre-/peri-menopausal. Tumors were predominantly ductal carcinoma, not otherwise specified (NOS) (81.3%), T1 (73.0%), grade 2 (59.7%), estrogen receptor-positive (ER+) (90.6%), and node-negative (82.0%). 70-GS and 80-GS results were available from 64 patients; 56.3% of tumors classified as 70-GS High Risk, and 82.8% Luminal-type, 9.4% HER2-type, and 7.8% Basal-type by 80-GS. Although pooled here for analysis, when examined separately, tumors of Chinese American patients were more frequently HER2-type (5/23; 21.7%) than tumors of Hong Kong patients (1/41, 2.4%) and had some higher risk clinical features, such as greater frequency of grade 3 classification (54.2%). Age-matched Cau patients were similar to Chinese patients in menopausal status (50.4% pre/peri-menopausal); age-matched AA patients were predominantly (58.6%) post-menopausal. Tumors of Cau patients were predominantly ductal carcinoma NOS (87.9%), T1 (73.4%), grade 2 (51.6%), node-negative (82.4%), ER+ (89.2%), 70-GS Low Risk (52.3%) and 80-GS Luminal-type (86.4%). Tumors of AA patients were predominantly ductal carcinoma, not otherwise specified (NOS) (86.7%), T1 (50.0%), grade 3 (53.6%), node-negative (79.3%), ER+ (72.7%), 70-GS High Risk (75.8%), and 80-GS Luminal-type (60.6%), although a substantial portion were 80-GS Basal-type (33.3%).

Conclusions: The current study revealed some disparities in clinical and molecular features of breast tumors between Chinese American and Hong Kong patients, and among Chinese, Cau, and AA patients. Some features typically associated with higher clinical risk were more prevalent in Chinese American patients than in Hong Kong patients, suggesting a possible interaction between genetics and lifestyle factors, and perhaps influenced by immigration. However, given the small sample size, these data should be interpreted with caution, and further study is needed to validate these trends. Future studies of breast cancer in ethnic subpopulations should incorporate evaluation of genomic profiling.

BluePrint Molecular Subtyping ResultsPatients Luminal-typeHER2-typeBasal-typeTotalChinese (pooled)53 (82.8%)6 (9.4%)5 (7.8%)64Hong Kong37 (90.2%)1 (2.4%)3 (7.3%)41US16 (69.6%)5 (21.7%)2 (8.7%)23Caucasian (US)114 (86.4%)6 (4.6%)12 (9.1%)132African-American (US)20 (60.6%)2 (6.1%)11 (33.3%)33

Citation Format: Ava Kwong, Sarah Untch, Heather M. Kling, Christine Finn, William Audeh, Vivian Shin, Sherene Ishtihar, Margaret Chen. Different MammaPrint and BluePrint molecular profiles and clinical-pathological features of early stage breast cancer in Chinese patients in the United States and Hong Kong [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-10-15.