American Association for Cancer Research

March 1 Cancer Research Highlights

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Selected Articles from the March 1, 2007 Issue

The articles referenced in this Highlights section will be available online in HTML and PDF formats to all interested users at no charge until the next issue of Cancer Research is published. Click on the article title to view the complete article.

View the Table of Contents for the March 1 issue of Cancer Research.


Gene Increases Estrogen, Not Breast Cancer

Haiman et al.

Page 1893

The CYP19A1 gene encodes the P450 enzyme aromatase, which is responsible for the final step in the biosynthesis of estrogens. In this study, Haiman et al. found haplotype-tagging SNPs and common haplotypes spanning the coding and proximal 5´ region of CYP19A1 to be significantly associated with a 10–20% increase in endogenous estrogen levels in postmenopausal women. No significant associations were observed, however, with these SNPs or common haplotypes and breast cancer risk. Thus, while genetic variation in CYP19A1 produces measurable differences in estrogen levels among postmenopausal women, the magnitude of the change was insufficient to contribute detectably to breast cancer.
 

Estrogens Promote ER-Negative Cancers

Gupta et al.
Page 2062

Gupta et al.Ovariectomy prevents the formation of both estrogen receptor (ER)–positive as well as ER-negative breast cancers, suggesting that even ER-negative breast cancers are dependent on ovarian hormones for their formation. Gupta et al. hypothesized that steroid hormones promote the outgrowth of ER-negative cancers by influencing host cell types distinct from the mammary epithelial cells. Increasing the levels of circulating estrogens sufficed to promote the formation and progression of ER-negative cancers, which was accompanied by a systemic increase in host angiogenesis and was attendant with the recruitment of bone marrow–derived stromal cells.  Furthermore, bone marrow cells from estrogen-treated mice were sufficient to promote tumor growth. These results revealed a novel mechanism by which estrogens promote the growth of ER-negative cancers.


Radiopharmaceutical Speeds Way to Individualized Treatments

Orlova et al.
Page 2178

Orlova et al.Molecular imaging of drug targets and biomarkers may facilitate the development and clinical use of individualized treatments using targeted therapeutics. The time to take a novel imaging agent from research to clinic can be reduced by avoiding complex biological production issues. Orlova et al. solved this issue by using peptide synthesis of Affibody molecules targeting the HER2 receptor to obtain a preparation suitable for radiolabeling at the clinic. Preclinical characterization showed specific tumor targeting, rapid biodistribution kinetics and blood clearance, and high-contrast gamma camera imaging 1 hour after injection. In patients, this radiopharmaceutical holds promise not only to localize tumors, but also to characterize them as HER2-positive, which then can influence treatment regimes.


Hedgehog Inhibitors Reduce Pancreatic Metastasis

Feldmann et al.
Page 2187

In the context of pancreatic cancer, metastasis remains the most critical determinant of resectability and, hence, survival. The objective of this study was to determine whether Hedgehog signaling plays a role in pancreatic invasion and metastasis, as this likely will have profound clinical implications.  Feldmann et al. confirmed pharmacologic Hedgehog pathway inhibition as a valid therapeutic strategy for pancreatic cancer, and demonstrated for the first time its particular efficacy against metastatic spread. By targeting specific cellular subpopulations likely involved in tumor initiation at metastatic sites, Hedgehog inhibitors may provide a new paradigm for therapy of disseminated malignancies, particularly when used in combination with conventional antimetabolites that reduce “bulk” tumor size.


Dasatinib Promising for Triple-Negative Breast Tumors

Huang et al.
Page 2226

Huang et al.Dasatinib is a novel kinase inhibitor recently approved for use in chronic myeloid leukemia, though its utility in solid tumors has only begun to be explored. To aid in clinical development, Huang et al. identified candidate molecular markers predictive of response to dasatinib in vitro and further assessed their predictive utility in additional cell lines. Most strikingly, the subgroup of breast tumors predicted to respond to dasatinib are “triple-negative” (ER–, PR–, and HER2–), suggesting that dasatinib may represent a valuable treatment option in this difficult-to-treat population. Clinical studies are now underway to determine the activity of dasatinib in these patients.