Development of Expression Based Biomarkers in NSCLC: A Study of Intratumor Heterogeneity Using FFPE Tissue
There is considerable interest in the use of gene expression data to generate predictive and prognostic biomarkers from archived non-small cell lung cancer (NSCLC) tissue (Potti et al., 2006). In early stage disease, up to twenty FFPE blocks are available from each patient. Since NSCLC tumors exhibit histological diversity, it is possible that areas of individual tumors represented by different FFPE blocks will exhibit distinct molecular profiles (Sakurada et al., 2008). This intratumoral heterogeneity represents a potential problem for the development of biomarkers from NSCLC tissue. This study examines gene expression data in multiple FFPE blocks taken from individual patients. Variations in gene expression are analysed between:
- FFPE blocks of individual patients
- Whole FFPE sections and macrodissected tumor tissue
- Individual patients
- Disease histologies (squamous and adenocarcinoma
The study also evaluates the impact of these variations on powering clinical biomarker discovery studies.