From:  Current status of molecular diagnostics for lung cancer

 Utility of different methods for detection of LC molecular targets

Gene/AlterationsVariant-specific PCRSequencing of relevant DNA fragmentsFISHIHCDNA-based NGSRNA-based NGSOther methods
EGFR mutations in exons 18, 19 and 21+++−−++++++Capillary gel electrophoresis is reliable for detection of exon 19 deletions and insertions
EGFR exon 20 insertions+++−−++++++Capillary gel electrophoresis is reliable for detection of exon 20 insertions
BRAF mutations+++−−++++++
KRAS mutations+++−−++++++
ERBB2 (HER2) exon 20 insertions+++−−++++++Capillary gel electrophoresis is reliable for detection of exon 20 insertions
MET exon 14 skipping mutations+−−−++++Comparison of expression of mutated vs. wild-type allele
ALK fusions+−+++++++PCR test for unbalanced 5’/3’-end expression
ROS1 fusions+−++−/+++++PCR test for unbalanced 5’/3’-end expression (?)
RET fusions+−−−++++PCR test for unbalanced 5’/3’-end expression
NTRK1−3 fusions+−+++++++PCR test for unbalanced 5’/3’-end expression
TMB−−−−++++ (?)
PD-L1 expression−−−+−−

+++: highly reliable method; ++: method with some limitations; +: method with significant limitations; −: inappropriate method; (?): not enough evidence. The blank cells indicate that no methods other than the ones marked by “+” symbols have been sufficiently validated for the testing of this molecular marker. FISH: fluorescence in situ hybridization; IHC: immunohistochemistry; NGS: next-generation sequencing; TMB: tumor mutation burden