Molecular Diagnostics in Neoplasia Flashcards
Gene mutations
substitutions, deletions, insertions
tumor suppressor genes and oncogenes
histone/ epigenetic regulation genes
Sanger Sequencing
Size descrimination by capillary electrophoresis
Amplification of target regions of DNA
Run through capillary electrophoresis with control fragments of known size
good to look for insertion, deletion, expansion, contraction
Increased progression free survival and overall survival in pts with wild type RAS (KRAS and NRAS) and BRAF with MAB+ standard chemo in pts with advanced dz
KRAS codon 12 G12D mutation
Patient not eligible for anti EGFR therapy
Next generation sequencing AKA massively parallel sequencing
DNA fragmented
DNA ligated to unique uniquely coded sequenced (primer site, hybridization site, unique identifier)
SNA hybridized to substrate (flow cell, bead)
Sequencing
Bioinformatics
Microsatellite instability
By fragment length analysis/capillary electrophoresis
Microsatellite instability via pyrosequencing
EFGR mutations in non-small cell lung cancer
EFGR mutatios in exons 18,19,20,21 (kinase domain)
Rarely foind in association with other mutations (KRAS, ALK, ect)
Priamrily in adenocarcinoma histology, never smokers, females, asians
10% of US pts (35% of asians)
Pt with eligible mutations for targeted FDA approved small molecular inhibitors
testing for EFGR mutations part of NCCN guidelines
Some mutations confer resistance to FDA approved small molecular inhibitors
HPV caqn turn off P53 as well as RB and P16
Causes cevervical dysplasia and can lead to head and neck dysplasia
What testin shoulde be used to ID lynch syndrome pts
microsatellate instability
Reflex MLH1 hypermethylatiohn
Relex BRAF mutation testing
MMR protein expression by IHC
MLH1 hypermethylation
Gene sequencing
PCR
Epigenetics/ Regulatory Alterations
DNA methylations
miRNA
viral effect
Patient specimen (FFPE) sent for KRAS, NRAS, BRAF, and P13KCA testing by next generation sequencing
Pathways to Cancer
Gene Mutations
Rearrangements
Copy number variations
Gene expression
Epigenetics/ regulatory alterations
Labs for genetic testing need to be regulated by
CLIA