Table 1.

Methods to diagnose ALK rearrangements

TestAdvantagesDisadvantages
Break-apart FISHCan detect any rearrangementCost
Performed on FFPE tissueExpertise required
Used clinically in crizotinib trialsOften difficult to interpret
CISHCostExpertise required
Performed on FFPE tissueOften difficult to interpret
Simultaneous histology evaluation
Reverse transcriptase PCRNeeds minimal materialWill not identify new fusions
Can identify fusion partnersRNA degradation
Possibility of contamination
IHCCostLow-level ALK expression
Can be performed in any laboratoryNo preferred antibody as yet
Performed on FFPE tissues

Abbreviations: FFPE, formalin-fixed paraffin-embedded; IHC, immunohistochemistry.