Differences in gene and protein expression and the effects of race/ethnicity on breast cancer subtypes
Menée auprès de deux cohortes distinctes (376 et 255 patientes, âge médian : 50 ans), cette étude analyse l'association entre des variations dans l'expression de 177 protéines, l'appartenance ethnique et le sous-type histologique de cancer du sein
Background: Differences in gene or protein expression patterns between breast cancers according to race/ethnicity and cancer subtype. Methods: Transcriptional profiling was performed using Affymetrix HG-U133A platform in 376 patients and reverse phase protein array analysis (RPPA) was done for 177 proteins in 255 patients from a separate cohort. Unsupervised clustering was conducted, as well as supervised comparison by race and tumor subtype. Standard statistical methods, BRB-Array tools and Ingenuity Pathways software packages were used to analyze the data. Results: Median age was 50 years in both cohorts. In the RPPA cohort 54.5% of the tumors were HR-positive, 20.7% HER2-positive and 24.71% triple-negative (TNBC). One hundred and forty-seven (57.6%), 47 (18.43%), 46 (18.1%) of the patients were White, Hispanic and Black, respectively. Unsupervised hierarchal clustering of the protein expression data showed no distinct clusters by race (p-values were 0.492, 0.489 and 0.494 for the HR-positive, HER2-positive and TNBC tumors respectively). In the gene expression cohort, 54.2% of the tumors were HR-positive, 16.5% HER2-positive and 29.3% TNBC. Two hundred and sixteen (57.5%), 111 (29.52%), and 32 (8.52%) patients were white, Hispanic and black, respectively. No probe set with an FDR < 0.05 showed an association with race by breast cancer subtype; similar results were obtained using pathway and gene set enrichment analysis methods. Conclusions: we did not detect significant variation in RNA or protein expression comparing different race/ethnicity groups of women with breast cancer Impact: More research on the complex network of factors that result in outcomes differences among race/ethnicities is needed.