Researchers led by the Indiana University School of Medicine's George Sandusky were able to extract usable DNA from formalin-fixed celloidin-embedded tissue, as they write in the American Journal of Translational Research. The researchers extracted DNA from more than 180 samples, including formalin-fixed celloidin-embedded tissue samples that were more than 70 years old as well as formalin-fixed paraffin-embedded tissue samples from the 1970s through the 2000s. From this, the researchers found that "celloidin-embedded and paraffin-embedded tissues yielded the highest DNA concentration and greatest DNA quality, while the formalin in various concentrations, and long term formalin/ethanol-stored tissue yielded both the lowest DNA concentration and quality of the tissues tested."
Also in the American Journal of Translational Research, researchers at Eli Lilly report on genes specifically expressed in the Hedgehog pathway. They extracted RNA from blood, hair follicle, and skin of healthy people and analyzed the expression of specific genes using quantitative real-time PCR and microarrays. The Lilly researchers note that skin was the best sample source. "Whether processed by robust multiarray average or microarray suite 5 (MAS5), expression patterns of individual samples showed co-clustered signals; both normalization methods were equally effective for unsupervised analysis," they write, adding that "this work provides the basis for selection of a surrogate tissue and an expression analysis-based approach to evaluate pathway-related genes as markers of pharmacodynamic effect with novel inhibitors of the Hh pathway."