USE OF A CDNA MICROARRAY TO ANALYZE GENE-EXPRESSION PATTERNS IN HUMANCANCER

The development and progression of cancer(1-3) and the experimental re versal of tumorigenicity(4,5) are accompanied by complex changes in pa tterns of gene expression. Microarrays of cDNA provide a powerful tool for studying these complex phenomena(6-8). The tumorigenic properties of a human melanoma cell line, UACC-903, can be suppressed by introdu ction of a normal human chromosome 6, resulting in a reduction of grow th rate, restoration of contact inhibition, and suppression of both so ft agar clonogenicity and tumorigenicity in nude mice(4,5,9). We used a high density microarray of 1,161 DNA elements to search for differen ces in gene expression associated with tumour suppression in this syst em. Fluorescent probes for hybridization were derived from two sources of cellular mRNA [UACC-903 and UACC-903(+6)] which were labelled with different fluors to provide a direct and internally controlled compar ison of the mRNA levels corresponding to each arrayed gene. The fluore scence signals representing hybridization to each arrayed gene were an alysed to determine the relative abundance in the two samples of mRNAs corresponding to each gene. Previously unrecognized alterations in th e expression of specific genes provide leads for further investigation of the genetic basis of the tumorigenic phenotype of these cells. DNA microarrays, containing 1,161 total elements.