HER2 status in operable breast cancers from Vietnamese women: Analysis by immunohistochemistry (IHC) and automated silver enhanced in situ hybridization (SISH)

AbstractBackground. HER2 amplification has been reported to occur in 19–30% of breast cancers in women from Western countries. Little is known about the HER2 status in breast cancers from Vietnamese women. The aim of this study was to assess the HER2 status in Vietnamese women with operable breast cancer using immunohistochemistry and silver in situ hybridization techniques. Material and method. Tissue blocks from 242 Vietnamese women with invasive primary breast carcinoma were stained by immunohistochemistry (IHC) and a dual silver in situ hybridization (SISH) for assessing HER2 status. The analysis followed international recommendations with a semi-quantitative grading of the reaction in four levels, “0”, “1+”, “2+” and “3+”. The HER2 gene amplification was assessed by calculating the ratio of HER2/chromosome 17 in 20 tumor cell nuclei. A ratio of 2.2 indicated tumors with gene amplification. A ratio between 1.8 and 2.2 was equivocal. Results. Using ...