screening and identification of the nucleic acid aptamers in nasopharyngeal carcinoma to screen the nucleic acid aptamers of the eb viruspositive nasopharyngeal carcinoma cells we used selex technology and synthesized in vitro a 78nucleotide random dna library we used normal nasopharyngeal epithelial cells and eb viruspositive low differentiated nasopharyngeal carcinoma cells as target to conduct 10 cycles of screening cloning sequencing and identification of the aptamers the fluorescence produced by the combination of the sublibrary and the target cells gained intensity gradually with the increase in the number of screening cycles indicating elevated binding capacity the cluster analysis showed that the aptamers can be divided into three families with two of the families having the common conserved sequence in this study by screening nucleic acid aptamers for affinity and specificity we established an initial aptamer library for eb viruspositive nasopharyngeal carcinoma cells