Progress in Genomics
Don't be scared off by the title. This is a brief, but very good, summary from Medscape about progress in personalized medicine/genomics. These terms refer to making treatment decisions based on a better understanding of the genetic composition of a particular tumor--e.g. what are the features or mutations and what might respond to any one therapy. In the long run, there is real hope that carefully chosen treatments will be more effective, that fewer people will endure treatments that are not so likely to help them, and that side effects will be reduced.
Here is an excerpt and then a link:
Genetic Studies Identify Breast Cancer Patient Subpopulations
In a large screening study of > 7000 patients with breast cancer and no mutation in BRCA, investigators noted that a second genetic mutation, known as CHEK2, identifies a population of individuals with a substantially increased risk of developing breast cancer. For women with a truncating mutation in CHEK2, it was estimated that the lifetime risk of developing breast cancer was approximately 20% vs a baseline population risk of 6%. However, the lifetime risk with CHEK2 increased to 28%, 34%, and 44% for women with a second-degree relative, first-degree relative, and both a first- and second-degree relative, respectively, who had been diagnosed with breast cancer. These data provide strong support for exploration of the presence of a CHEK2 mutation in women with a family history of breast cancer but no evidence of a BRCA mutation.
Genetic studies can also help identify subpopulations of patients more or less likely to respond to specific treatments. In a phase 1 trial examining the toxicity and efficacy of the 3-drug combination of pegylated liposomal doxorubicin, bevacizumab, and temsirolimus in patients with breast cancer and gynecologic malignancies, an overall response rate of 20% was noted. However, in a group of 25 patients with a documented mutation in PIK3CA or with a PTEN loss, there was a response rate of 36%, and an additional 16% of patients maintained a stable disease state for at least 6 months. These provocative data, which must be confirmed by others, suggest that the mutational status of a cancer may strongly influence the clinical response to these specific agents and may serve as valid biomarkers to predict the utility of this regimen.
Similarly, in a study examining the influence of BRCA mutational status on the activity of neoadjuvant chemotherapy for breast cancer, investigators found a 46% complete response rate among a group of 57 women who had mutations in BRCA1 vs a complete response rate of only 13% in 23 women with BRCA2 abnormalities and a rate of 22% in 237 patients without mutations in BRCA. These data again support the potential predictive role of specific genetic abnormalities in defining the probability of a major response to systemic therapy.
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