Assessment of Her‐2/neu status using immunocytochemistry and fluorescence in situ hybridization on fine‐needle aspiration cytology smears: Experience from a tertiary care centre in India

Abstract

Breast carcinoma shows amplification/overexpression of Her-2/neu in ∼20-30% of cases. The determination of Her-2/neu expression accurately is vital in clinical practice as it has significant predictive value and eligibility for anti Her-2/neu therapy. Amplification and overexpression of Her-2/neu gene is traditionally identified by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) on tissue sections; only a few studies have evaluated feasibility of these techniques on cytological smears. One hundred cases of breast cancer with fine-needle aspiration cytology (FNAC) samples and corresponding surgically resected specimen were selected. Immunocytochemistry (ICC) and FISH for Her-2/neu was done on FNA smears, whereas IHC was performed on corresponding tissue sections. Diagnostic accuracy of ICC was 99% when compared with IHC. Comparison of FISH results with IHC showed 100% concordance. Unlike many centers in West, FNAC is still routinely performed in developing countries like India where vast majority of breast cancer cases present as palpable lumps. The high rates of accuracy of ICC and FISH for Her-2/neu detection can make FNAC a relevant first line of investigation as a cost effective model with a rapid turn-around time, providing complete information necessary for initial management of breast cancer patients.

Assessment of Hormone Receptor and Human Epidermal Growth Factor Receptor 2 Status in Breast Carcinoma Using Thin-Prep Cytology Fine Needle Aspiration Cytology FISH Experience From China

“…Different detection technique and procedure used in this study together with the heterogeneity of tumor cells may be the reasons of this inconsistency. 26 , 27 In contrary to Bedard et al, 33 the specificity of FNAC HER2 ICC in our study was very high (97.3%), and the positive predictive value was 97.1%. It is worth to note that all FNAC specimens were votexed for 20 to 30 minutes before slide preparation in our laboratory, this might explain a relatively high specificity of HER2 ICC in this study.…”

“…Additionally, the heterogeneity of positive cells in the tumor is also one of the key causes for inconsistencies between cytology and histology results. 26 , 27 …”

Reliability of immunocytochemistry and fluorescence in situ hybridization on fine‐needle aspiration cytology samples of breast cancers: A comparative study

“…Perfect correlation was found between the paired samples in concordance with the literature. [27][28][29][30] The sensitivity and specificity were both 100%, meaning that if HER2 was not amplified in the surgical specimen, no amplification was detected in the FNAB sample either and vice versa. HER2 amplification detected by FISH carried out on aspirates has shown a 100% PPV.…”

Updated UK Recommendations for HER2 assessment in breast cancer

“…However, if fine needle aspiration (FNA) is the only material available, or in metastatic disease, some evidence indicates that ISH is reliable for assessing HER2 status in liquid-based and cell block preparations. 25 In the case of metastatic bone lesions that require HER2 assessment, it should be noted that decalcification techniques have the potential to influence immunohistochemical assessment in a detrimental manner and such decalcified samples should be tested with ISH methods. 26 27 …”