The recent issue of the National Cancer Institute (NCI) Cancer Bulletin (April 20, 2010) highlights an article by researchers from the Washington University School of Medicine in St. Louis, reported in the April 15 issue of Nature.  The study was presented at the recent American Association for Cancer Research Annual Meeting in Washington, DC, as part of a mini-symposium on genetic sequencing.
 
The study patient was a 44 year old African American woman with triple negative inflammatory breast cancer.  The triple negative or 'basal-like' subtype is more common in younger women as well as African American women.  Studies have shown that these tumors are very aggressive and have a poor prognosis.
 
This group of researchers had the unique opportunity to study how cancer cells change as the disease progresses by doing genome analysis of four DNA samples from a patient diagnosed with triple negative inflammatory breast cancer.  Samples were obtained from the primary breast tumor, brain metastasis, and normal blood cells.  Using cells from the original tumor researchers were able to grow tumor in a mouse (this is a xenograft).
 
Genetic mutations, structural changes, and differences in the number of gene copies were studied in the four samples.  Analysis of the data confirmed earlier reports that basal-like breast cancers have unstable genomes.  There were mutations common to all three tumors (primary, metastatic and xenograft) but most of the original mutations in the original tumor were also present in the metastatic and mouse tumors.
 
While a single patient genomic study doesn't provide robust data it does allow for comparison of the tumor in different sites and examine the similarity and changes that occur from primary tumor to metastasis.  Dr. Patricia Steeg, head of the Women's Cancer Section in the National Cancer Institute's Laboratory of Molecular Pharmacology was quoted as saying, "this study is a true tour de force in genomics."  Dr. Steeg has been studying breast cancer metastasis for much of her career and is currently leading the work of the Center of Excellence program studying brain metastasis of breast cancer.
 
A previous study, published last year, reported on whole-genome sequencing to study both primary tumor and metastasis.  A significant difference in the two studies is the time from primary tumor to metastasis.  In the study published last year it was 9 years from primary tumor to metastasis and less than a year in the current report.
 
Genome studies are fast becoming more feasible economically and are being done on larger groups of patients.  The Washington University School of Medicine study group is already doing tumor-normal genome comparisons and will publish larger data sets and analysis in the future.
 
To read the full NCI Cancer Bulletin article:
http://www.cancer.gov/ncicancerbulletin/042010/page7