mutation detection on lung cancer cytological specimens by the novel fully automated PCR-based Idylla Mutation Assay.

AIMS

In everyday practice, epidermal growth factor receptor () testing is centralised in referral laboratories that receive paucicellular cytological specimens. Ideally, testing should be carried out in the centre where the patient is diagnosed such that the most cellular slide can be selected from in-house collected cytological material. However, available techniques are little standardised and difficult to be implemented in settings with little expertise in molecular testing. The Idylla prototype assay is a rapid and fully automated test which may easily be adopted by a wider number of pathological centres. This study assessed whether an Idylla prototype assay can be reliably applied to cytological lung cancer specimens.

METHODS

The limit of detection (LOD) of the Idylla prototype assay was assessed by cell line dilution studies. A total of 10 ng was directly placed inside an Idylla prototype assay cartridge. Idylla results were compared with fragment length (exon 19 del) and Taqman assays.

RESULTS

The Idylla prototype assay showed an LOD of 1% mutant allele and yielded valid results in 74/76 (97.3%) samples, detecting all the mutant cases (n=32) identified by standard techniques; in addition, Idylla detected two low abundance exon 19 deletions and two G719X exon 18 point mutations, not covered by our standard reference method.

CONCLUSIONS

Idylla prototype assay is sensitive on extracted DNA and can reliably be applied on cytological samples, enabling implementation of testing even in less experienced diagnostic units.