Breast Analyte Control^DR

Suitable tissue able to reflect different expression levels of Estrogen Receptor (ER), Progesterone Receptor (PR) and Human Epidermal growth Factor Receptor 2 (HER2) is time consuming and sometimes difficult to obtain. HistoCyte Laboratories Ltd have been able to develop a product that can be employed to demonstrate the relative sensitivity of your assay.

For ER and PR there are at least two cell lines with a heterogeneous expression of these proteins. The others are either homogeneously positive or negative. The heterogeneous cells react by more or less of the cells staining depending on whether the assay over or under performs. For HER2 there are two 1+ cell lines that provide the sensitivity to determine whether the assay has worked effectively.

Figure 1 shows the relative number of HER2 receptors associated with each HER2 score (see the blue line). This was performed on the Oracle HER2 cell lines and illustrates the absence of any linear correlation across all four scores (see yellow dotted line). The only linear correlation seen is between 0, 1+ and 2+ (see red dotted line). If the assay was to fluctuate up or down, the 1+ cell line will stain less towards negative or score as higher akin to a 2+. In a known standardised 1+ cell line, this assay fluctuation is potentially easier to determine than in a 2+ cell. The 2+ cell score is often the score of most discordance2. HistoCyte Laboratories Ltd have developed control material robust and cost effective enough for same slide use.