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Overexpression of the HER2/neu oncogene is observed in approximately 30% of human breast carcinoma specimens. HER2/neu overexpression is a negative prognostic factor in breast cancer patients. Cancer cells that overexpress HER2/neu may also be less sensitive to chemotherapy. In order to further de®ne mechanisms by which HER2/neu overexpression drives neoplastic cell growth and chemoresistance, antisense oligonucleotides (ODNs) have been utilized to selectively down-regulate HER2/neu expression in human breast cancer cells. Such antisense ODNs suppress HER2/neu mRNA and protein levels in a dose-dependent, sequence-speci®c manner. Down-regulation of HER2/neu expression in HER2/neu overexpressing breast cancer cells inhibits cell cycle progression in G 0 /G 1 and results in apoptotic cell death. In tissue culture studies, combined treatment of HER2/ neu overexpressing breast cancer cells with HER2/neu antisense ODNs and conventional chemotherapeutic agents results in synergistic inhibition of cancer cell growth and activation of apoptotic cell death mechanisms. These studies have been extended to demonstrate synergistic antitumor eects following systemic treatment with antisense ODNs plus doxorubicin in nude mice bearing human breast carcinoma xenografts. Collectively these ®ndings demonstrate that HER2/neu overexpression stimulates anti-apoptotic cell survival mechanisms and suggest that HER2/neu antisense ODNs may be of use in cancer therapeutics. Oncogene (2000) 19, 6138 ± 6143.

In our experience, intraprocedural thromboembolic events occur despite the use of cerebral protection devices, but are rare. Notably these complications appeared to occur at the time of lesion crossing by distal cerebral protection devices. These thromboembolic events can be successfully treated if the complication is rapidly identified and the physician is adequately prepared and proficient in neurorescue techniques.

Mutations involving the adenomatous polyposis coli (APC) tumor suppressor gene leading to activation of beta-catenin have been identified in the majority of sporadic colonic adenocarcinomas and in essentially all colonic tumors from patients with Familial Adenomatous Polyposis. The C57BL/6J-APC(min) (Min) mouse, which carries a germ line mutation in the murine homolog of the APC gene is a useful model for intestinal adenoma formation linked to loss of APC activity. One of the critical downstream molecules regulated by APC is beta-catenin; molecular targeting of beta-catenin is, thus, an attractive chemopreventative strategy in colon cancer. Antisense oligodeoxynucleotides (AODNs) capable of downregulating murine beta-catenin have been identified. ANALYSIS OF beta-CATENIN PROTEIN EXPRESSION IN LIVER TISSUE AND INTESTINAL ADENOMAS: Adenomas harvested from mice treated for 7 days with beta-catenin AODNs demonstrated clear downregulation of beta-catenin expression, which was accompanied by a significant reduction in proliferation. There was no effect on proliferation in normal intestinal epithelium. Min mice treated systemically with beta-catenin AODNs over a 6-week period had a statistically significant reduction in the number of intestinal adenomas. These studies provide direct evidence that targeted suppression of beta-catenin inhibits the formation of intestinal adenomas in APC-mutant mice. Furthermore, these studies suggest that molecular targeting of beta-catenin holds significant promise as a chemopreventative strategy in colon cancer.