Sets of genetic markers for specific tumor classes are described, as well
as methods of identifying a biological sample based on these markers.
Genes that are differentially expressed between different stages of
colorectal tumors are identified. Genes that are differentially expressed
between tumors that have metastasized to the regional lymph nodes and
tumors that have not metastasized to the regional lymph nodes are
identified. Changes in gene expression pattern between two samples or
between a sample and a control may be used to determine tumor stage. Also
described are diagnostic, prognostic, and therapeutic screening uses for
these markers, as well as oligonucleotide arrays comprising these
markers.