Determination of HER-2 status on FNAC material from breast carcinomas usingin situhybridization with dual chromogen visualization with silver enhancement (dual SISH)

Elsa Beraki,Torill Sauer

doi:10.4103/1742-6413.70968

Abstract

During the last years, HER-2 status kits and protocols for chromogen visualization of hybridization signals have come on the market. The first generation using chromogen visualization used single color probes. The second generation, now emerging on the market, uses dual chromogen visualization. The aim of this study has been to test a new dual color chromogen kit (Ventana INFORM HER2 Dual Colour ISH Roche®) and compare the results with our in-house method(s). The material consisted primarily of cytological material from invasive breast carcinomas in 49 women. Dual SISH was done on all 49 cytological and histological specimens. The histological specimens were treated according to the manufacturer’s recommendations. The procedure was modified in several steps in order to adapt it to the cytological material. Hybridization failed in two cytological specimens. Dual SISH showed concordant results on cytological and histological material as to amplified/not amplified. The included cases had the same HER-2 expression in the invasive and the in situ components on histology. Four IDC showed HER-2 amplification (8.5%). Polysomy was found in two cases. All dual SISH results except for one concurred with the results of the in-house method(s) (1/47=2.1%). The dual SISH is suitable for cytological examination of HER-2 status. The protocol must be optimized for cytological material.

Highlights

The procedure was modified in several steps in order to adapt it to the cytological material [Table 1]
Axillary lymph node metastases were found in 25 cases, whereas 22 cases were N0
A FAQ web site[14] to these guidelines answer the question “Do the guidelines exclude HER2 testing of cytology specimens that have been fixed in 95% ethanol rather than formalin?” as follows: “Since cytology specimens are not ordinarily fixed in formalin, that sentence is not directly applicable, but labs performing HER2 testing on such specimens must document that they validated their methods and achieved acceptable concordance, in this case by comparing staining of alcohol fixed cytology specimens with routinely processed tissue

Summary

Introduction

Prognostic and predictive markers such as estrogen and progesterone receptor status, HER-2 status and Ki-67 index are routinely evaluated in all carcinomas according to the recommendations of the Norwegian Breast Cancer Group (www.nbcg.no)[1] and national recommendations All of the markers can be evaluated on cytological material, but is most commonly used in metastatic settings where surgery or a biopsy is not feasible.[3] Cytological material is suitable for examining HER-2 using in situ hybridization (ISH)[3,4,5,6] and capping of tumor cell nuclei (meaning that in a histological section only part of, and not the whole nucleus, is represented) is not an issue. FISH (fluorescent in situ hybridization) protocols for HER-2 determination can normally be used on cytological material without or with only minor changes in the procedure for histological specimens

Methods

Results

Conclusion