Abstract

A method is disclosed for the analysis of gene expression in human biopsy that is useful in the diagnosis and prognosis of disease and evaluation of risk for disease. The method comprises the steps of compiling data regarding the level of expression of certain individual cloned gene sequences from patients having defined pathological conditions and from normal patients and thereafter identifying sequences that characterize the pathological condition.The data regarding the expression of the individual cloned genes are stored in a defined pattern or array. Replicas of this array are hybridized to radioactive probes made using the RNA isolated from biopsy tissue. The extent of hybridization of the probe to each of the cloned sequences is proportional to the level of expression of the cloned sequence in the tissue from which the probe was made. This may be done by exposing the hybridized clones to x-ray film and scanning the x-ray films to quantify the cloned sequences. This is preferably done with a computer driven scanner. The digitized data may be processed using a computer program. The method may be used to determine the expression of cloned sequences in human colon biopsy samples of malignant of premalignant tissue as well as for monitoring the effects of chemotherapeutic agents.An apparatus is also disclosed for use in carrying out an automated assay.