From Introduction: Lung cancer is the biggest cause of cancer death in the UK (CRUK, 2014). It is a biologically very
diverse disease, and shows striking variation seen in histological appearances, which are reflect high
levels of genomic changes with concomitant diversity of tumour cellular biology (reviewed in
Shames and Wistuba, 2014). Despite this, until a decade ago, a simple classification into two
categories, small cell or non-small cell, was the only one relevant to disease management. Small-cell
carcinoma generally gave a good initial response to chemotherapy, whereas only non-small cell
disease was amenable to surgical cure and there was no clinical reason for pathologists to attempt
further classification of non-small cell carcinomas. This review will examine the subsequent
developments in lung cancer diagnosis and look forward to how emerging technologies and
improved understanding of tumour biology are likely to further transform the pathological diagnosis
of this disease