AIM:To identify esophageal cancer related gene2(ECRG2)associated proteins and their possible interactions withECRG2 gene.METHODS:In the yeast forward two-hybrid system,ECRG2was fused with the DNA-binding domain(DBD)of Gal4 andhuman fetal liver cDNA library was fused with thetranscriptional activation domain(AD)of Gal4.We performeda high-stringency scale procedure to screen ECRG2 againsthuman fetal liver cDNA library and characterized positivesby sequence analysis.RESULTS:We found the following 9 putatively associatedproteins.They were metallothionein2A,metallothioneinlH,metallothioneinlG,ferritin,erythrocyte membrane proteinband4.2,mitochondrial ribosomal protein S12,hypotheticalprotein FLJ10101,and a novel gene whose cDNA was foundto have no strong homology to any other previouslycharacterized gene whose DDBJ/EMBL/GenBank accessionnumber is AF422192 mapped to human chromosome 14q31.CONCLUSION:MT,a potential interaction partner forECRG2,might be involved in the regulation of cellproliferation and apoptosis,and in various physiologicalprocesses.Determination of a reliability score for each singleprotein-protein interaction,especially interaction of ECRG2and MT,permits the assignment of ECRG2 and unannotatedproteins to biological pathways.A further understanding ofthe association between ECRG2 and MT should facilitatethe functions of ECRG2 gene.