University of Louisville
Gene Expression in Breast Carcinomas from Patients with Ethnical Differences
Institution
University of Louisville
Faculty Advisor/ Mentor
Jim Wittliff; Sarah A. Andres
Abstract
African American women often exhibit more aggressive breast cancer and have a higher mortality rate than Caucasian women. Socioeconomic differences do not explain all differences observed in clinical behavior of breast carcinomas. Our goal was to determine dissimilarities in gene expression of breast carcinoma biopsies of white and black patients and to evaluate if they are related to cancer behavior. Using an IRB-approved biorepository and database, gene expression levels were compared in biopsies from white and black patients utilizing microarray analyses of LCM-procured carcinoma cells. Frozen tissue sections from de-identified patients with primary breast carcinoma were utilized for qPCR analyses. Total RNA was extracted with the RNeasyÒ Mini Kit (Qiagen), evaluated with the Bioanalyzer (Agilent) and reverse transcribed using iScript (Biorad). QPCR was performed using Power SybrÒ Green (Applied Biosystems), and relative expression was calculated using Universal Human Reference RNA (Stratagene) as the calibrator and ACTB for normalization. Examination of candidate gene expression levels from microarray revealed that CARD11, TRAPPC2L, CRYBB2P1 and PDHA1 exhibited significant differences in carcinomas of African American patients compared to Caucasian patients. Of these genes, only PDHA1 expression was correlated with overall survival (P=0.05) when the entire population of 245 breast carcinoma patients was stratified by median expression level without regard to race. Only PDHA1 expression assessed by microarray was correlated with overall survival of white patients (P=0.04) when stratified by race and gene expression level. Using a comparison of expression levels of PDHA1, CRYBB2 and TRAPPC2L from qPCR and microarray, CRYBB2 was correlated (P=0.01), while PDHA1 was not. Although dissimilarities in gene expression levels were observed in black and white patients, preliminary evaluation of a gene subset to personalize prognosis assessment requires additional studies. Supported in part by the grant NCI Summer Research Program, PHS Grant 1 R25 CA 134283-1 to AMB.
Gene Expression in Breast Carcinomas from Patients with Ethnical Differences
African American women often exhibit more aggressive breast cancer and have a higher mortality rate than Caucasian women. Socioeconomic differences do not explain all differences observed in clinical behavior of breast carcinomas. Our goal was to determine dissimilarities in gene expression of breast carcinoma biopsies of white and black patients and to evaluate if they are related to cancer behavior. Using an IRB-approved biorepository and database, gene expression levels were compared in biopsies from white and black patients utilizing microarray analyses of LCM-procured carcinoma cells. Frozen tissue sections from de-identified patients with primary breast carcinoma were utilized for qPCR analyses. Total RNA was extracted with the RNeasyÒ Mini Kit (Qiagen), evaluated with the Bioanalyzer (Agilent) and reverse transcribed using iScript (Biorad). QPCR was performed using Power SybrÒ Green (Applied Biosystems), and relative expression was calculated using Universal Human Reference RNA (Stratagene) as the calibrator and ACTB for normalization. Examination of candidate gene expression levels from microarray revealed that CARD11, TRAPPC2L, CRYBB2P1 and PDHA1 exhibited significant differences in carcinomas of African American patients compared to Caucasian patients. Of these genes, only PDHA1 expression was correlated with overall survival (P=0.05) when the entire population of 245 breast carcinoma patients was stratified by median expression level without regard to race. Only PDHA1 expression assessed by microarray was correlated with overall survival of white patients (P=0.04) when stratified by race and gene expression level. Using a comparison of expression levels of PDHA1, CRYBB2 and TRAPPC2L from qPCR and microarray, CRYBB2 was correlated (P=0.01), while PDHA1 was not. Although dissimilarities in gene expression levels were observed in black and white patients, preliminary evaluation of a gene subset to personalize prognosis assessment requires additional studies. Supported in part by the grant NCI Summer Research Program, PHS Grant 1 R25 CA 134283-1 to AMB.