Test Description

Genes included on the CancerNext test are evaluated by next generation sequencing (NGS) of the coding exons and well into the flanking 5’ and 3’ ends of the introns and untranslated regions. Variants in regions complicated by pseudogene interference, variant calls not satisfying depth of coverage and variant allele frequency quality thresholds, and potentially homozygous variants are verified by Sanger sequencing. The MSH3 polyalanine repeat region is excluded from analysis. The inversion of coding exons 1-7 of the MSH2 gene is detected by NGS and confirmed by multiplex ligation-dependent probe amplification (MLPA) or PCR and agarose gel electrophoresis. Clinically significant intronic findings beyond 5 base pairs are always reported. Intronic variants of uncertain or unlikely clinical significance are not reported beyond 5 base pairs from the splice junction. ​ ​

Gross deletion/duplication analysis is performed for CancerNext genes (excluding AXIN2, HOXB13, MBD4, MLH3, MSH3, POLD1, and POLE) using a customized pipeline using a combination of third-party coverage-based tools and custom methodologies with confirmatory MLPA and/or targeted chromosomal microarray. For GREM1, only the status of the 40kb 5’ UTR gross duplication is analyzed and reported. For EPCAM, only gross deletions encompassing the 3’ end of the gene are reported. For NTHL1, only full-gene gross deletions and duplications are detected. For APC, all promoter 1B gross deletions as well as single nucleotide substitutions within the promoter 1B YY1 binding motif (NM_001127511 c.-196_-186) are analyzed and reported. Gross deletions and duplications of exons 11-15 of PMS2 are reflexed to long-range PCR and gel electrophoresis and/or sequencing to determine if the event occurs within PMS2 or pseudogene PMS2CL.​