Fig. 1

Percent incidence and typical histologies of lung cancer subtypes. Percent incidences shown are specific to American populations [5]. Locations of lung cancers depicted are generalized sites typical of lung tumorigenesis for subtypes. Lung cancers are classified into two major types: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). All forms of pulmonary carcinomas may be distributed throughout the lung but some locations are more typical for certain classes. SCLC primarily originates from central airways, and neuroendocrine cells are thought to be the precursors of this tumor type. As a heterogeneous disease, NSCLC is further subdivided into three major subtypes: squamous cell carcinoma (SqCC), large cell carcinoma (LCC) and adenocarcinoma (AC). Percentage distributions of NSCLC histologies total to NSCLC percentage (83.4 %), where remaining histogies (non-small cell carcinoma and other specified carcinomas) are not depicted. SqCC predominately originates from central airways and segmental bronchi and are thought to arise from basal cells. LCC are classified as tumors without general features associated with SCLC, SqCC and AC and may arise anywhere in the lung. The most common type of NSCLC is AC and is thought to principally arise from type II pneumocytes and club cells