To characterize breast tumors and metastases, fine-needle aspiration cytology (FNAB) can be a favorable first choice. However, the diagnostic accuracy of ancillary tests applied to FNAB samples is yet to be validated.Patients and Methods:
We examined 110 breast cancer patients' paired cytological and surgical resection specimens evaluated between 2005 and 2014. Comparison of ER and Her2 immunocytochemical (ICC) and immunohistochemical (IHC) staining and HER2 fluorescence in situ hybridization (FISH) was performed.Results:
Significant difference (p < 0.001) and moderate correlation (κ = 0.446) were noted between results of 97 paired ICC an IHC reactions for ER expression. ICC for ER status had a sensitivity of 75%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 38.2%. Significant difference (p = 0.012) and moderate correlation (κ = 0.541) were found between results of 77 paired ICC an IHC reactions for Her2 expression. The Her2 ICC had a sensitivity of 54%, specificity of 95.4%, PPV of 66.7%, and NPV of 92.6%. The results of FISH carried out on 23 paired samples of FNAB and surgical specimens indicated perfect correlation (κ = 1.000) and no significant difference (p = 1.000). FISH performed on FNAB has sensitivity, specificity, PPV, and NPV of 100%.Conclusion:
The correlation of ICC and IHC is moderate regarding ER and Her2 expression of the same tumor. FISH performed on FNAB samples is suitable to categorize primary and metastatic breast cancer in regard of HER2 gene amplification status and can be used as a predictive test in respect of therapies targeting HER2. Diagn. Cytopathol. 2016;44:466–471. © 2016 Wiley Periodicals, Inc.