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Genetic studies have identified mutations in key regulators of the Wnt/[beta]-catenin pathway in a variety of cancers, most frequently in colon cancers. However, whether the pathway is activated in clinical cancer samples is not easily determined, and therefore it is useful to find markers that could be surrogates to show activation of the Wnt/[beta]-catenin pathway. Gene expression profiles were analyzed in SW620, a colon cancer cell line in which [beta]-catenin levels are stabilized as a consequence of truncated adenomatous polyposis coli and were compared with profiles of the same cells transfected with antisense oligodeoxynucleotides. Treatment of cells with [beta]-catenin antisense oligodeoxynucleotides resulted in a decrease in the levels of axin2 and human naked cuticle (hnkd) mRNAs. Interestingly, the proteins encoded by both of these mRNAs are known inhibitors of the [beta]-catenin pathway. In 30 human cell lines derived from different origins, axin2 and hnkd were expressed only in human colon cancer cell lines that are known to have activating mutations in the Wnt/[beta]-catenin pathway. Further, levels of both axin2 and hnkd mRNA were also found to be elevated in about 65% of laser microdissected cells from human colon tumors compared with laser microdissected cells of normal morphology from the same patient samples. The increased expression of axin2 and hnkd correlated with truncations in adenomatous polyposis coli in the same patient samples. These results reveal that it is possible to detect activation of a carcinogenic pathway in human cancer samples with specific markers.

Genes linked to brahma (brm), a stimulator of homeotic gene expression in Drosophila, were screened to establish possible regulators of Hox gene expression. brg1, a cloned murine gene, may be a DNA-dependent ATPase or a helicase, because it encodes a member of the DEGH proteins family. Hox gene regulation and other regulatory routes may involve the action of brg1.

The Antennapedia Complex (ANT-C) of Drosophila (D) pseudoobscura was cloned to determine the rigidity of its organization and to provide further understanding of its evolutionary changes. Results revealed that the structural characteristics of ANT-C in D pseudoobscura is highly identical with that found in D melanogaster, except that the psudoobscura ANT-C lacks the z2 gene. In addition, in D pseudoobscura, the Deformed gene's orientation is inverted and has a 5' to 3' transcription direction. These indicate that the ANT-C structure is not rigid and can be altered even during a short period of evolutionary divergence.