Molecular determinations of EGFR and EML4-ALK on a single slide of NSCLC tissue

Introduction Tyrosine kinase inhibitors (TKIs) and anti-anaplastic lymphoma kinase (ALK) agents are highly effective for the treatment of non-small cell lung cancer (NSCLC) patients harbouring specific alterations, and molecular characterisation of the tumour is needed even when limited tumour material is available. Methods 20 patients with a known epidermal growth factor receptor (EGFR) gene status were enrolled: 10 had mutated and 10 had wild type tumours. FISH analysis was performed on one cytological or histological sample to determine EML4-ALK status, after which the same cells scraped off each slide were used to evaluate the EGFR status. Results In the 10 EGFR mutated patients, molecular analysis showed the same results as those obtained before the FISH test. One patient with an EGFR mutation also showed an EML4-ALK translocation, and both FISH-positive and FISH-negative cells maintained the EGFR mutation. Conclusions EGFR mutation analysis can be performed on the same sample previously submitted to the EML4-ALK FISH procedure.