DNA and RNA analyses in detection of genetic predisposition to cancer

Abstract

The introduction of liquid handling robots made possible their application in DNA or RNA isolation, normalization of samples' concentration, PCR preparation, etc. Parallel development of software and hardware enabled complete automatic management of large sample series in genetic testing, including data transfer without any user intervention. Nowadays leading companies offer capillary sequencers analyzing simultaneously up to 96 samples amplified by means of cycling sequencing with fluorescent dyes. Improved " chemistry" and gels' composition enabled accurate sequencing of fragments of 1000 bp in length. Another system (GSFLX machine 2007), based on massive parallel sequencing by cyclic technology, can generate 100 Mb of genomic sequence in a single run (about 4.5 hours). Real-time PCR techniques with TaqMan® probes (or TaqMan® MGB probes) have become commonly used in laboratory practice. MLPA technique used in detection of rearrangements in genes associated with hereditary cancers allows the determination of exon copy number. The presence of deletions or duplications of exons or whole genes can be analyzed by that method. Commercial kits are available for genes with a well-documented association with hereditary cancers: ATM, BRCA1, BRCA2, CHECK1, MLH1, MSH2, MSH6, PMS2, APC, FANCA, FANCD2, PTCH, BMPR1A, SMAD4, TP53, RB1, CDKN2A-CDKN2B, WT1, CDH1, MEN1, NF1, NF2, STK11, SMARCB1.