Correlating quantitative gene expression to radiologic response to docetaxel (DTX) in formalin-fixed paraffin-embedded (FFPE) tumor tissue from patients (pts) with metastatic non-small cell lung cancer (NSCLC)

Abstract

7030 Background: We hypothesized that TaqMan RT-PCR could be used to measure expression levels of individual genes in FFPE tumor samples, which might correlate with response to DTX (Taxotere™). Methods: We identified 140 pts who had received single-agent DTX for metastatic NSCLC, and had FFPE tissue available at our center. Radiologic response was determined according to standard criteria. We prepared an H&E slide from each block to verify that the tissue was nearly all tumor. A 40 micron slice was cut from the block, deparaffinized, deproteinized, RNA extracted using phenol/chloroform, and converted to cDNA. Based on published reports and proposed mechanisms of resistance to taxanes, we designed primers and probes to analyze the following genes: β-TUB1, β-TUB3, α-TUB1, α-TUB2, MRP1, MRP2, MRP4, MRP7, PGP, BCRP, LRP, GSTpi, BCL2, BCLxl, BAX, Survivin, MAD2, p53, transket, MAGE2, MCL1, HTERT, klf4, lklf, HER2, EGFR. Results: 53 blocks were identified as suitable for analysis. Of these, 32 blocks yielded RNA sufficient for TaqMan RT-PCR. Expression of the following genes was higher in pts with resistant disease: β-TUB3, p53, BAX, GSTpi, and HTERT (p<.05 by Jonckheere test for association). Of these, β-TUB3 showed the strongest association (p=0.014). Conclusions: FFPE tissue can be used to perform expression analysis of individual genes using high-throughput, TaqMan RT-PCR. These data justify a prospective trial to see whether the genes identified in this study predict resistance of NSCLC to DTX. This work was supported by Aventis Pharmaceuticals. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Aventis Pharmaceuticals Aventis Pharmaceuticals