A very sensitive multiplexed and high-throughput gene chip assay (MAPS) has need developed for drug discovery that measures multiple mRNA species in each well of a 96-well microplate. For example, the expression of a group of cancer related and control genes can be tested simultaneously within each well. It is proposed to modify this sensitive technology for use in detection of exfoliated cells. MAPS will address an unmet need of the diagnostic industry to make use of gene chip technology in the detection of exfoliated cells from biological samples. Proprietary methods allow DNA array technology to be used with increased sensitivity and reliability yet decreased cost. Hybridization specificity for each targeted gene is confirmed within each sample. The assay is currently in use for high-throughput drug discovery. The method is sensitive detecting 0.2 copies of mRNA per cell, 100,000 cells per sample. The applicants propose to enhance the method to develop a reliable and sensitive screen to detect the presence of exfoliated cancer cells in clinical samples. PROPOSED COMMERCIAL APPLICATION: The need for a high throughput multiple mRNA assay for detection of exfoliated cancer cells exists for sensitive and specific detection of exfoliated cells from cancer patients. The method described here has the potential of detection of exfoliated cells without amplification.