The challenge of NSCLC diagnosis and predictive analysis on small samples. Practical approach of a working group

► The diagnosis of lung cancer involves the identification and complete classification of malignancy. ► New therapeutic options require specific subtyping of NSCLCs and, increasingly, the identification of therapeutically predictive molecular markers, to determine the safest and most effective choice of drugs. ► Small diagnostic sample size and tumour complexity often prevent specific subtyping on morphological grounds alone (NSCLC-NOS). ► Immunohistochemistry can predict the likely NSCLC subtype (squamous cell vs. adenocarcinoma) in most NSCLC-NOS cases. ► Tissue sampling should be maximized whenever feasible and deemed clinically safe, reducing the need for re-biopsy for additional studies. ► Tissue handling, processing and sectioning should minimize wastage and optimize use of tissue for diagnosis.