Methylation level and mRNA expression of CpG island of HER2 gene in breast cancer and its adjacent tissues

doi:10.3969/j.issn.1673-8640.2020.05.019

Abstract

Abstract:

Objective To investigate the methylation level and mRNA expression of CpG island of human epidermal growth factor receptor 2（HER2） gene in breast cancer and its adjacent tissues. Methods Totally,50 samples of breast cancer tissues and adjacent tissues confirmed by pathology were collected. The methylation rate of CpG island of HER2 promoter,the expression of HER2 mRNA and the expression of HER2 protein were determined by pyrosequencing,real-time polymerase chain reaction（PCR） and immunohistochemistry,respectively. Results The relative expression of HER2 mRNA in HER2 positive breast cancer tissues was higher than that in HER2 negative breast cancer tissues（P<0.05）,and there was no statistical significance in the methylation rate of CpG island of HER2 promoter（P>0.05）. The methylation rate of HER2 promoter CpG island in HER2 negative breast cancer tissues was higher than that in adjacent tissues（P<0.05）,while the expression of HER2 mRNA was lower than that in adjacent tissues（P<0.05）. There was no statistical significance in the methylation rate of CpG island of HER2 promoter and the expression of HER2 mRNA between HER2 positive breast cancer and adjacent tissues and between the 2 groups of adjacent tissues（P>0.05）. Conclusions Hypomethylation of CpG island of HER2 promoter may be one of the mechanisms of high expression of HER2 mRNA in breast cancer adjacent tissues of HER2 negative group.

Key words: Human epidermal growth factor receptor 2, CpG island, Methylation, Breast cancer

CLC Number:

R446.62

JIN Shu, ZHU Qi, ZHU Yuan, YUAN Ya, CAI Xiaoyao, ZHANG Ji, YAN Peiyi. Methylation level and mRNA expression of CpG island of HER2 gene in breast cancer and its adjacent tissues[J]. Laboratory Medicine, 2020, 35(5): 481-486.

Figures/Tables 7

References 21

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引物名称	序列（5'~3'）	产物大小/bp
F1	AGGGATTTTTAGAGGAAAAGTGTGAG	151
R1	CCCCCTCCAACTACATTCCA
S1	GTGAGAAAGGTTGTAGGTAATTTA

引物名称	序列（5'~3'）	产物大小/bp
F1	AGGGATTTTTAGAGGAAAAGTGTGAG	151
R1	CCCCCTCCAACTACATTCCA
S1	GTGAGAAAGGTTGTAGGTAATTTA

基因名称	序列（ 5'~3'）	产物大小/bp
HER2	F:GCCCTGTGCCCGAGTGTGCTA R:CAGAAATGCCAGGCTCCCAAAGAT	124
GAPDH	F:GGATTTGGTCGTATTGGG R:GGAAGATGGTGATGGGATT	205

基因名称	序列（ 5'~3'）	产物大小/bp
HER2	F:GCCCTGTGCCCGAGTGTGCTA R:CAGAAATGCCAGGCTCCCAAAGAT	124
GAPDH	F:GGATTTGGTCGTATTGGG R:GGAAGATGGTGATGGGATT	205

HER2	例数	HER2 mRNA	甲基化位点						平均甲基化率/%
HER2	例数	HER2 mRNA	1/%	2/%	3/%	4/%	5/%	6/%	平均甲基化率/%
阳性	17	0.15（0.05~0.41）	15.87±6.52	14.43±4.46	11.66±4.38	17.10±5.63	17.16±3.67	10.60±3.79	14.47±4.56
阴性	33	0.06（0.02~0.11）	19.05±10.11	15.53±7.09	13.33±6.57	18.74±8.42	17.49±6.05	11.46±5.46	15.93±7.03
统计值		2.12	1.34	0.67	1.07	0.82	0.20	0.59	0.89
P值		0.03	0.25	0.56	0.35	0.47	0.84	0.56	0.44