Liver chip and gene shaving. 
A comprehensive profile of genes expressed at the mRNA level in various human tissues is considered to be important for understanding the molecular mechanisms of the tissue-specific function and the pathogenesis of related diseases.  Here, the gene expression profiling in three human digestive tissues, liver, stomach, and pancreas, was catalogued by generating a large number of expressed sequence tags, and clarified how quantitatively the gene expressions are different.  After assembling the redundant clones among three tissues, the results showed that only 1.7% among the assembled genes was expressed commonly in the investigated tissues.  These results suggest that the significant functional divergences in different tissues must be related to the divergence of the gene expression profiles.  Recently, microarray technologies are widely used.  Considering the results that different genes express in different tissues, however, it is important to spot the cDNAs derived from the same tissues or cells examined to acquire information efficiently.  For the study of digestive diseases, we constructed an in-house microarray by using the cDNA sets derived from the digestive tissues (liver and gastric chip).  In addition, because the amount of information acquired by the microarray analyses is huge, the power of bioinformatics for unifying the obtained data is indispensable.  Some examples of the strategies for handling the microarray data obtained by our in-house microarrays are shown in this article.