The effect of delay in fixation on HER2 expression in invasive carcinoma of the breast assessed with immunohistochemistry and in situ hybridisation.

Aims: Accurate assessment of HER2 status is essential for selection of patients for HER2-targeted treatment such as trastuzumab. This study investigated the hypothesis that delayed fixation impairs HER2 assessment.

Methods: 9 carcinomas were received fresh, and samples were fixed immediately or put in fixative at time intervals up to 24 h.

Concordance of HER2 status assessed on needle core biopsy and surgical specimens of invasive carcinoma of the breast.

Aims: Human epidermal growth factor receptor 2 (HER2) status of invasive breast cancers is vital for selection of patients for trastuzumab treatment. This study aimed to assess the level of agreement of HER2 status in core biopsy and excision specimens using immunohistochemistry, with in-situ hybridisation for equivocal cases.

Methods And Results: 300 consecutive invasive carcinomas with core biopsy and surgical specimens had HER2 assessed on both specimens.

Breast carcinomas with borderline (2+) HER2 immunohistochemistry: percentage of cells with complete membrane staining for HER2 and the frequency of HER2 amplification.

Aim: HER2 status is vital for selecting breast cancer patients for trastuzumab treatment. One recommended approach is to assess immunohistochemical staining and then perform in situ hybridisation on those tumours with a borderline (2+) immunohistochemical result. This audit aimed to assess the value of the percentage of immunohistochemical staining in 2+ tumours in selecting tumours for in-situ hybridisation.