Association of HER2 genetic heterogeneity with clinicopathological characteristics in breast cancer / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To introduce the College of American Pathologists/American College of Medical Genetics Cytogenetics Resource Committee criteria for genetic heterogeneity (GH) in HER2 testing, and investigate the clinicopathological significance of HER2 genetic heterogeneity in invasive breast cancer.</p><p><b>METHODS</b>The clinical parameters of 100 cases of invasive breast carcinomas were collected. HER2 expression level and HER2 gene copy number in formalin-fixed and paraffin embedded tumor samples were detected by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), and the relationship between HER2 gene GH and clinicopathological characteristics were analyzed.</p><p><b>RESULTS</b>Among the 100 patients, HER2 gene GH was observed in 20 (20%) cases. When the number of HER2 amplified cells was more than 25%, the frequencies of FISH positive were higher than those cases with less than 25% HER2 amplified cells. The results showed that HER2 gene GH was associated with the degree of HER2 protein expression (P=0.004), and ER expression (P=0.002).</p><p><b>CONCLUSION</b>HER2 gene GH may be correlated with the HER2 protein IHC 1+/2+, and ER expression in breast carcinoma. It is important for doctors to avoid ignoring or only counting FISH positive cells leading to incorrect diagnosis for these patients.</p>