Comparison Of Prognostic Value Of Ki67 And HER2 In Breast Cancer

Part Ⅰ:Differential expression of Ki67 and HER2 in breast cancer cellsObjective To study the differential expression of Ki67 and HER2 in MCF-7 and MDA-MB-231 cells and explore the correlations with invasive and metastatic capability.Methods qPCR and Western Blot experimental techniques were performed to investigate the mRNA and protein expression of Ki67 and HER2 in breast cancer cells MCF-7 and MDA-MB-231, and the correlations between invasive and metastatic capability and the differential expression of Ki67 and HER2 was analyzed.Results Ki67 mRNA relative level in MDA-MB-231 cell with high alility of invasion and metastasis was about 3.31 bolds of the relative level in MCF-7 cell with low alility of invasion and metastasis (P< 0.01), HER2 mRNA relative level in MDA-MB-231 cell with high alility of invasion and metastasis was about 1.79 bolds of the relative level in MCF-7 cell with low alility of invasion and metastasis (P< 0.05). The expressional defferences of Ki67 mRNA was higher than HER2 mRNA in two different cells (3.31 vs.1.79). Ki67 and HER2 protein levels were higher in MDA-MB-231 cell than in MCF-7 cell, this is identical to mRNA level.Conclusions overexpression of Ki67 and HER2 were relative to invasive and metastatic capability of breast cancer cells.Part Ⅱ:Quantum dots-based multispectral fluorescent imaging to quantitatively study co-expression of Ki67 and HER2 in breast cancerObjective To study the prognostic value of co-expression of Ki67 and HER2 in breast cancer.Methods Quantum dot-based double-color in-situ quantitative fluorescent imaging technique was employed to investigate the expression of Ki67 and HER2 in breast cancer (BC) specimens, and the correlations between 8-year disease free survival (8-DFS) and the co-expression of Ki67 and HER2 was analyzed.Results Ki67 was expressed in cancer cell nucleus as clear red fluorescence and HER2 in cancer cell membrane as bright green fluorescence, and the sharp image color and spectrum contrast made it easy for signal separation and quantification. Both Ki67 and HER2 expression alone was significantly correlated with 8-DFS (P< 0.05). However, the two molecules had different weights in terms of negative impacts on clinical prognosis. The median 8-DFS was statistically significantly shorter in High-Ki67 High-HER2 subgroup than Low-Ki67 High-HER2 subgroup (11.7 vs.60.1 months, P< 0.05), shorter in High-Ki67 Low-HER2 subgroup than Low-Ki67 Low-HER2 subgroup (16.4 vs.96.0 months, P< 0.01), shorter in High-Ki67 High-HER2 subgroup than Low-Ki67 Low-HER2 subgroup (11.7 vs. 96.0 months, P< 0.01), but there was no statistically significant differences in median 8-DFS between High-Ki67 Low-HER2 subgroup and High-Ki67 High HER2 subgroup (11.7 vs.16.4 months, P= 0.586). The hazard ratio (HR) of Ki67 negative impact on 8-DFS was about 3 folds of HER2 (HR 4.493 vs.1.481).Conclusions Quantum-dot based fluorescent imaging techniques could help the quantitative study on the collaborative expression of Ki67 and HER2 in breast cancer, and the negative impact of Ki67 on breast cancer prognosis is about 3 folds of HER2.