Abstract:

BACKGROUND: HER2 status assessment is an important biological index for the treatment and prognosis of invasive breast cancer. Pre-treatment of tissues such as immobilization, dehydration, transparency and dewaxing is a necessary procedure for HER2 protein and gene detection after pathological paraffin sections, and also an important factor affecting immunohistochemistry and fluorescence in situ hybridization.

OBJECTIVE: To explore the application value of environment-friendly biological tissue sample preparation kit in fluorescence in situ hybridization detection of HER2 protein 2-positive invasive breast cancer.

METHODS: 402 invasive breast cancer specimens were collected from Shantou Central Hospital from January 2015 to March 2019. The same specimens were semi-dissected and randomly divided into two groups. The control group was treated by traditional reagent formaldehyde immobilization-ethanol dehydration-xylene transparency and dewaxing, and paraffin sections were made. The experimental group was treated with formaldehyde immobilization-ethanol dehydration-xylene transparent dewaxing. Environment-friendly biological tissue sample preparation kit (including environmentally friendly stationary fluid, dehydration fluid, transparent liquid, dewaxing fluid) was used to make slices. The expression of HER2 protein was detected by immunohistochemistry. The amplification of HER2 gene was detected by fluorescence in situ hybridization in 131 invasive breast cancer specimens with positive HER2 protein expression.

RESULTS AND CONCLUSION: The expression of HER2 protein in both experimental and control groups was specific and cell localization was correct. There were no significant differences in HER2 protein positive rate, uncertainty rate, and negative rate between the two groups (P > 0.05).The coincidence rate of HER2 protein expression between the two groups was 99.00%. The background of HER2 gene was clear in both groups, and the signals of HER2 and Ch17 double probes were clear. There was no cross-reaction and the double probe signal was precisely located in the nucleus of cancer cells. There was no significant difference in the number of successful cells between the two groups (P > 0.05). There was no significant difference in the positive rate and negative rate of HER2 gene amplification between the two groups (P > 0.05). The coincidence rate of HER2 gene amplification between the two groups was 97.71%. The average signal number of HER2 gene and the ratio of HER2/cells in both groups were all equal. There was no significant difference in the mean number of Ch17 signal, Ch17/cell ratio and HER2/Ch17 ratio between the two groups (P > 0.05). There was no significant difference in the total positive rate of HER2 between the two groups (P > 0.05). The results showed that compared with the traditional reagents, the invasive breast cancer samples prepared by environment-friendly bio-tissue sample preparation kit had no effect on HER2 protein expression. The expression of HER2 protein does not affect the amplification of HER2 gene, which can meet the needs of clinical detection.

Key words: invasive breast cancer, human epidermal growth factor receptor 2, immunohistochemistry, fluorescence in situ hybridization, amplification, fixation, dehydration, transparency