Ki-67 Expression by Immunohistochemistry and Quantitative Real-Time Polymerase Chain Reaction as Predictor of Clinical Response to Neoadjuvant Chemotherapy in Locally Advanced Breast Cancer

Background. Chemotherapy has become a standard of treatment in managing breast cancer. To achieve proper treatment for\ud the right patients, the predictive marker is needed. Ki-67 is a biomarker of proliferation for solid tumor. Studies mentioned\ud association of Ki-67 expression with chemotherapy response. The study aims are to evaluate whether Ki-67 expression detected\ud by immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR) may predict clinical response\ud to neoadjuvant chemotherapy in breast cancer. Methods.This study utilized a longitudinal study. IHC and qRT-PCR methods were\ud used for detection of Ki-67 expression. Chemotherapy response was calculated using RECIST. Data were analyzed with Chi-square\ud and Wilcoxon???s test. Results. There were 48 subjects in this study. Analysis of Ki-67 expression with chemotherapy response has\ud a significant correlation with ???? = 0.025 (<0.05), OR: 1.69, confidence interval (95% CI) 1.022???2.810. Analysis of Ki-67 mRNA\ud expression with chemotherapy response has a significant correlation ???? = 0.002 (<0.05), OR: 6.85, confidence interval (95% CI)\ud 1.064???44.193. Detection of Ki-67 expression using IHC and qRT-PCR has similar results, ???? = 0.012 (