General information
The SALSA MLPA Probemix P483 HER gene family is a research use only (RUO) assay for the detection of deletions or duplications in the HER family of receptor tyrosine kinases. This gene family is comprised of four members promoting cell proliferation, motility and invasion via signalling through homo- or heterodimerization: EGFR (ERBB1/HER1), ERBB2 (HER2), ERBB3 (HER3), and ERBB4 (HER4) (Sergina and Moasser, 2007).

Amplifications in the Human Epidermal Growth Factor Receptor (HER) gene family are associated with a high invasiveness of human cancers, most notably in breast cancer (Gan et al, 2013; Sergina and Moasser, 2007). As transmembrane proteins, the products of these genes are suitable targets for anticancer drugs. For example, breast cancer patients with tumours overexpressing Her2 (20-30% of breast tumours; Mitri et al. 2012) are treated with trastuzumab (Herceptin), which impairs receptor signalling by binding to its extracellular domain.

EGFR amplifications have been observed in a variety of cancers, including glioblastomas and colorectal carcinoma (Ayati et al. 2020). These amplifications are sometimes paired with rearrangements, such as EGFRvIII (deletion of exons 2-7; Gan et al. 2013) rendering the receptor constitutively active.

This SALSA MLPA probemix is not CE/FDA registered for use in diagnostic procedures. Purchase of this product includes a limited license for research purposes.

Probemix content
The SALSA MLPA Probemix P483-A1 HER gene family contains 54 MLPA probes with amplification products between 132 and 508 nucleotides (nt). This includes nine probes for EGFR, eight probes for ERBB2, four probes for ERBB3, and five probes for ERBB4. Furthermore, this probemix contains 14 probes targeting the regions flanking these four genes, as well as regions on the other arm of their respective chromosomes. This includes two probes for WSB1, in the CEP17 region, which is used as an internal control for HER2 amplification calling in other techniques (Allison, 2017).

In addition, 14 reference probes are included that target relatively copy number stable regions in various cancer types including breast cancer, glioblastoma and colorectal carcinoma. Probe sequences and the identity of the genes detected by the reference probes are available online (www.mrcholland.com).

This probemix contains nine quality control fragments generating amplification products between 64 and 105 nt: four DNA Quantity fragments (Q-fragments), two DNA Denaturation fragments (D-fragments), one Benchmark fragment, and one chromosome X and one chromosome Y-specific fragment. More information on how to interpret observations on these control fragments can be found in the MLPA General Protocol and online at www.mrcholland.com.