Microarray gene expression

RR Brentani MD PhD^a, D Carraro PhD^a, LFL Reis PhD^a, A Fiorini PhD^a, H Brentani PhD^b, MA Koike-Folgueira MD PhD^c, MM Brentani MD^c

^aLudwig Institute for Cancer Research, Sao Paulo, Brazil, ^bHospital do Câncer A.C.Camargo, Sao Paulo, Brazil, ^cLaboratório de Oncologia Experimental, Dept of Radiology, Faculdade de Medicina da Universidad Sao Paulo, Sao Paulo, Brazil

We have recently finished a massive genomic effort by obtaining and sequencing over a million ORESTES(Open Reading frame Expressed Sequence Tags)from various human tumors(PNAS etc)of which about 800,000 are deposited in GenBank. From the corresponding cDNA bank we employed 4800 to construct a microarray chip. These clones were selected on the basis of size(between 400 and 700 nucleotides); lack of repetitive sequences; distance from the first polyadenylation site (750 to 1000 nucleotides upstream)and displaying only one hit in the genome. This array has been used so far to investigate if there is a differential profile between responders and nonresponders to neoadjuvant chemo in advanced breast cancer cases and to find differences between normal gastric mucosa, gastritis, metaplasia and cancer in stomach biopsies. These preliminary results indicate that our chip is sufficiently powerful to allow us to address several clinically important questions.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in plenary session 803 (Risk & assessment).