Archived paraffin-embedded and fresh frozen NSCLC tumor tissue will be obtained via the Department of Pathology and the National University Tissue Repository respectively. Clinico-pathological characteristics will be obtained from the case records, Pathology and Tissue Repository. DNA will be isolated using standard techniques. Sequencing of genes in the EGFR signaling pathway: EGFR, KRAS, ErbB2, ErbB3, MET, PI3K, and BRAF as well as FGFR4. Unstained slides from the paraffin-embedded tissue will be obtained and subjected to fluoresce in vitro hybridization (FISH) for breakpoints in the EML4 and ALK genes as previously described. For cases that have been snap-frozen, RNA will be extracted and EML4-ALK fusions will be confirmed using RT-PCR and pre-specified primers. To analyse the expression of proteins of putative relevance to EGFR function (such as EGFR, ErbB2, ErbB3, AKT, MET, STAT, ERK, MAPK, cyclin D1, C/EBPa), downstream effects of EGFR: cell proliferation (Ki-67), angiogenesis (CD34, VEGF-A), apoptosis (bcl-2), metastasis, and hormonal influence (oestrogen and progesterone receptors, aromatase), TMA technology will be utilised. The status of the tumor suppressor genes PTEN and C/EBPa will be analysed.