The Royal College of Pathologists of Australasia Quality Assurance Program: Immunohistochemistry Breast Marker Audit Overview 2005-2015.

The Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) Anatomical Pathology provides a comprehensive External Quality Assurance (EQA) exercise to review the reporting of immunohistochemistry (IHC) and in-situ hybridization (ISH) breast markers through an audit of clinical results. The aim of this exercise was to provide information regarding the quality of breast marker testing within clinical laboratories from 2005 to 2015. This comprehensive audit included estrogen, progesterone, and HER2 marker reporting.

Microwaves for chromogenic in situ hybridization.

In situ hybridization can be employed in formalin-fixed, paraffin-embedded tissue sections (FFPT) and allows direct visualization of amplified genes and chromosomes in individual cell nuclei. Fluorescence in situ hybridization (FISH) is the most widely employed method, but the fluorescence preparations suffer from the main disadvantages of fading over time and poor visualization, the latter making it difficult to accurately separate invasive from in situ cancer cells. Chromogenic in situ hybridization (CISH) is a viable alternative to FISH in FFPT as it employs a peroxidase reaction to visualize the chromogen thus allowing the convenience of bright field microscopy and the correlation of the visualized gene amplification with cytomorphology.

Microwave enhancement of CISH for HER2 oncogene.

We describe a modification to the prescribed procedure for the Zymed Spot-Light HER2 chromogenic in situ hybridization kit (84-0146, Zymed Laboratories, San Francisco, CA) by substituting the heat pretreatment step with MW irradiation in citrate buffer 10 mmol/L at pH 6.0 at 98 degrees C for 10 minutes and repeating the procedure afterenzyme digestion with time and temperature controlled in the Mega T/ T oven (Milestone s.r.

Refinement of immunohistologic parameters for Her2/neu scoring validation by FISH and CISH.

The conventional method of scoring Her2/neu immunostaining is recognized to result in a high false-positive rate among 2+ cases when compared with results obtained with fluorescence in situ hybridization (FISH); however, costs and convenience dictates that immunohistochemistry remains the screening test for Her2/neu status in patients with breast cancer. We describe refined criteria for scoring of Her2/neu on the basis of anatomic localization rather than the subjective assessment of intensity. The presence of a circumferential tram track pattern that results from the staining of apposing cell membranes in >25% of the tumor cells was necessary for a 3+ score (Her2/neu overexpressed) and the presence of the tram track pattern in <25% was scored 2+ (equivocal); granular and fragmented membrane staining was scored 1+ (negative).