Construction and Identification of Subtracted cDNA Library of Human Colorectal Carcinoma and Adjacent Paracancerous Tissues

Background: Suppression subtractive hybridization (SSH) is a mature method for isolation of differentially expressed genes. However, Construction of subtracted cDNA library of colorectal carcinoma tissue-specific genes and screening of the related genes by this method are infrequent. Aims: To construct subtracted cDNA library of human colorectal carcinoma and adjacent paracancerous tissues. Methods: The cDNA fragments of genes differentially expressed in colorectal carcin-oma and the adjacent paracancerous tissues were isolated by SSH method. Then these cDNA fragments were directly inserted into pGEM-T Easy vector to set up the subtractive library. The library was amplified with transformation of ■DH5α. Two hundred positive bacteria clones were randomly picked out and identified by colony polymerase chain reaction (PCR). Results: Among the 200 positive clones identified by PCR method, 176 showed 200～700 bp inserts. Conclusions: The subtracted cDNA library of genes differentially expressed in human colorectal carcinoma and the adjacent paracancerous tissues are successfully constructed, which will be beneficial in future screening and cloning of specific-expressed genes of colorectal carcinoma.