2021 Volume 70 Issue 3 Pages 489-496
In the manual HER2-FISH test for breast cancer, the observer measures the HER2 and CEP17 signals of more than 20 cancer cells and calculates the mean number of HER2 copies and the HER2/CEP17 ratio. However, the results obtained manually may differ depending on the observer. The purpose of this study is to examine the usefulness of the automatic counting method by having multiple observers perform manual and automatic counting on the same sample. Eight breast cancer cases determined to be HER2 protein 2+ by immunohistochemical staining were included. The average number of cells measured by the automatic counting method was 222. The manual method showed discrepancies in four of the eight cases. In these four cases, the average HER2 copy number between observers was significantly different. Three of the four cases that did not match in the manual method were negative in the automatic counting method. Compared with the visual method, the automatic counting method showed a high degree of consistency in the HER2-FISH test. The automatic counting method can measure a large number of cells, and highly objective and reproducible results can be obtained. The automatic counting method is also useful as a means of quality control and may contribute to improving the accuracy of the HER2-FISH test.
