A New Study of BRCA1 and BRCA2 in Breast Cancer Patients from ...

Posted by Matt Mealiffe, M.D. on May 24, 2012 in Blog, BRCA1, BRCA2, Breast Cancer | 0 comments

There?s a growing amount of information about the extent to which inherited BRCA1 and BRCA2 mutations play a role in breast and ovarian cancer risk in Asia.? A new paper adds to the available information for patients in Thailand and Pakistan.

In this international study, Dr. Fabienne Lesueur and colleagues studied a total of 207 breast cancer patients from Pakistan and Thailand.

• The 77 Pakistani patients were from a Hospital-based series of breast cancer cases in Balochistan province
• The 130 Thai patients were selected for early-onset breast cancer (121) or a breast cancer family history (9) such that the median age of breast cancer onset was in the mid-30s for this group

In the researchers? analysis combining the two groups of patients there were a total of 10 clearly deleterious mutations in the 207 breast cancer patients (there were 2 mutations that were each found in 2 patients).? Four of the 8 distinct mutations were in BRCA1, and four were in BRCA2.?

Four of the 77 patients from Pakistan (5.2%) had clearly deleterious mutations even though there was no selection of the cases studied for age or family history.

For the patients from Thailand, a total of 6 individuals out of 130 (4.6%) had a clearly deleterious mutation.

They also identified a number of variants of uncertain clinical signficance in the two genes.

Bottom Line from this Study Focused on BRCA1 and BRCA2 in Pakistan and Thailand

1. In the series of breast cancer patients from Pakistan, who were unselected for age of onset or family history, approximately 5 percent were found to have deleterious BRCA1 or BRCA2 mutations.

2. A similar percentage of individuals with deleterious mutations was found in the women with breast cancer from Thailand (who were primarily selected for this study based on early age of onset of breast cancer).

3. Because the researchers used mutation identification techniques* that do not identify all mutations and rearrangements in the genes, it is likely that the true frequency is actually somewhat higher than they reported.

* high-resolution melting curve analysis followed up by Sanger sequencing

Selected References

Ahmad J, Le Calvez-Kelm F, Daud S et al.? Detection of BRCA1/2 mutations in breast cancer patients from Thailand and Pakistan.? Clinical Genetics 2012 (published online ahead of print Apr 8 2012)

Curated List: BRCA1 and BRCA2 in Pakistan

Curated List: BRCA1 and BRCA2 in Thailand

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