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The aim of this study was to identify genes that are predictive of carcinogenic change in patients of oral leukoplakia (OLK) using a cancer-related microarray. Candidate biomarkers were discovered using the Oligo GEArray OHS-802 and validated on independent samples by semi-quantitative reverse transcription-PCR (RT-PCR) and real-time RT-PCR. Both the discovery and the validation cohorts of samples included normal oral tissues, OLK tissues and oral squamous cell carcinoma (OSCC) tissues. Based on the microarray results, we found that there were nine genes successively up-regulated or down-regulated more than 2-fold between the normal group and OLK group and then again between the OLK group and OSCC group. The expression levels of the nine signature genes had statistically significant differences (p<0.05) between the OLK and normal groups and between the OSCC and OLK groups. In summary, the expression of the 9 signature genes might be representative of OLK carcinogenesis. A cancer-related microarray was used to identify a panel of candidate biomarkers for determining carcinogenesis of OLK lesions, in combination with semi-quantitative and real-time RT-PCR to validate the results. Our data indicated that alterations in gene expression that result in carcinogenesis can be identified in precancerous oral tissues.

Fluorescent Linear Labelling technique is an effective, single-tube and linear amplification method. The sample cDNA was synthesized from total RNA, and was labelled antisense cRNA from double-stranded cDNA with T7RNA polymerase; it can be used for hybridization to oligonucleotide biochip. Fluorescent Linear Labelling Method can result in 50- to 100-fold higher degrees of amplification, and has been shown to retain information on transcript abundance, thus making it an efficient, robust technique for fluorescent labelling on biochip.

Oligo-microarray can be fabricated on modified surface of glass slides involving immobilization of oligonucleotides. In this study, glass slides were modified with acrylic acid-co-acrylamide copolymer and EDC (1-ethyl-3(3-dimethylaminopropyl)-carbodiimide)/NHS (N-hydroxysuccinimide) by covalent linkage method, and covalent immobilization of unmodified oligonucleotide on the glass surface was achieved. The platform with binding of stable and sensitive oligonucleotides was prepared for oligo-microarray fabrication. An optimum concentration of 0.5 g/L was used for spotting. The lengths of 26 to 70 mer oligonucleotides were immobilized on the surface efficiently. The spots were approximately 160 nm in diameter and their mean value of fluorescent intensity was measured in the range of 3.2 x 10(4) to 7.3 x 10(4) after hybridization. The modified glass surface was scanned by SEM and the dendritic structure was observed. Results showed that the process of preparation of the modified glass surface was simple and cost effective, and the modified surface can be used for the oligo-microarray fabrication and also attachment of protein, PNA etc., ((c) 2008 Wiley Periodicals, Inc.)

A rapid and sensitive microarray assay for the detection of HCV-1b was developed in our laboratory and a cDNA fragment library for HCV-1b cDNA microarray probes was constructed. The full-length cDNAs of HCV-1b were digested with restriction endonuclease Sau3A I and the fragments were cloned with the pMD18-T vectors. Positive clones were isolated and identified by sequencing. The cDNA microarray was prepared by spotting the gene fragment on the surface of an amido-modified glass slide using the robotics system and samples were fluorescent labeled by the restriction display PCR (RD-PCR) technique, In the present study, modified protocols were used for probe selection and hybridization temperature. The detection of a microarray was validated by the hybridization and the sequence analysis. A total of 22 different specific gene fragments of HCV-1b ranging from 250 to 750 bp were isolated and sequenced, and these fragments were further used as probes in the microarray preparation. The diagnostic validity of the microarray method was evaluated after the washing and scanning process. The results of hybridization and sequence data analysis showed a significant specificity and sensitivity in the detection of HCV-1b RNA. The method of preparing microarray probes by construction of cDNA fragments library was effective, rapid, and simple; the optimized microarray was sensitive in the clinical detection of HCV-1b. The RD-PCR technique for the sample labeling was useful for significantly increasing the sensitivity of the assay. The cDNA microarray assay can be widely used in the clinical diagnosis of HCV-1b.

To study the technology for establishing DNA microarrays for the diagnosis of HPV. HPV6, 11, 16 and 18 gene fragments were isolated and printed onto aminosilane-coated glass slides by PixSys 5500 microarray printer as probes to prepare the HPV. HPV samples, after labeled with Cy3 or Cy5, were hybridaized with the microarray followed by scanning for analysis. The experimental condition for preparing the HPV gene chips was investigated and the possibility of HPV genotying using DNA microarrays was discussed. The technique established in this study for preparing HPV DNA microarrays is applicable and has potential clinical application significance.