General information: The SALSA MLPA Probemix P380 Wilms’ tumour is a research use only (RUO) assay for the detection of deletions or duplications on chromosomal arms 1p, 1q, 16p, and 16q. This probemix can further be used to determine the copy number of MYCN on 2p24.3, FBXW7 on 4q31.3, WT1 on 11p13, TP53 on 17p13.1, and AMER1 (previously known as FAM123B) on Xq11.1.

Wilms’ tumour (WT) is the most common paediatric renal tumour. Most of the cases occur sporadically in otherwise normal children. However, a minority of cases is associated with other developmental abnormalities such as WARG, Denys-Drash, Beckwith-Wiedemann or Frasier syndrome. While the survival of children with Wilms’ tumour has increased to ~90%, the survival of patients with relapse is still disappointingly low (~50%). Copy number changes of certain chromosomal regions and genes have been found to be highly significant for prognosis. Tools to classify these high-risk Wilms’ tumour patients are needed to intensify the treatment and, in addition, to reduce the treatment burden of the low-risk patients. This assay has been developed for that purpose.

Probemix content: The SALSA MLPA Probemix P380-B1 Wilms’ tumour contains 53 MLPA probes with amplification products between 127 and 500 nucleotides (nt). This includes 7 probes for chromosomal arm 1p, 5 probes for 1q, 3 probes for 16p, 6 probes for 16q, and 3 probes each for the MYCN, FBXW7, WT1, TP53, and AMER1 genes. Additionally, flanking probes (for the 2p, 2q, 4q, 11p, 17p, Xp and Xq arms) are included to facilitate the determination of the extent of a deletion or duplication. In addition, 10 reference probes are included in this probemix, detecting autosomal chromosomal locations which have a relatively stable copy number in Wilms’ tumour samples. Probe sequences and the identity of the genes detected by the reference probes are available in Table 2b and online (www.mlpa.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.mlpa.com.