Haplotype analysis in Icelandic and Finnish BRCA2 999del5 breast cancer families

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldThe 999del5 mutation is the single, strong BRCA2 founder mutation in Iceland and the most common BRCA1/2 founder mutation in Finland. To evaluate the origin and time since spreading of the 999del5 mutation in Iceland and in Finland, we constructed haplotypes with polymorphic markers within and flanking the BRCA2 gene in a set of 18 Icelandic and 10 Finnish 999del5 breast cancer families. All Icelandic families analysed shared a common core haplotype of about 1.7 cM. The common ancestors for the Icelandic families studied were estimated to trace back to 340-1000 years, not excluding the possibility that the mutation was brought to Iceland during the settlement of the country. Analysis of the Finnish families revealed two distinct haplotypes. A rare one, found in three families in the old settlement region in southwestern Finland, shared a four-marker (0.5 cM) core haplotype with the Icelandic 999del5 haplotype. A distinct approximately 6 cM haplotype was shared by seven 999del5 Finnish families estimated to have a common ancestry 140-300 years ago. These families cluster in two geographical regions in Finland, in the very same area as those with the rare haplotype and also in the most eastern, late settlement region of Finland. The results may indicate a common ancient origin for the 999del5 mutation in Iceland and in Finland, but distinct mutational events cannot be ruled out. The surprising finding of the same mutation in two completely different haplotypes in a sparsely populated area in Finland may suggest gene conversion

The role of AIB1 and PAX2 in primary breast cancer: validation of AIB1 as a negative prognostic factor.

BackgroundThe steroid-receptor coactivator amplified in breast cancer one (AIB1) is implicated to be a prognostic factor, although the results are not unanimous. Recently its effect was suggested to be modified by paired box 2 gene product (PAX2).Patients and methodsUsing immunohistochemistry (IHC) AIB1 and PAX2 were investigated in two cohorts of early breast cancer, including systemically untreated premenopausal lymph-node-negative women and pre- and postmenopausal women receiving tamoxifen.ResultsAIB1 scores were available for 490 patients and PAX2 scores were available for 463 patients. High AIB1 was a negative prognostic factor for distant disease-free survival (DDFS, P = 0.02) and overall survival (OS, P < 0.001) in systemically untreated women, while no prognostic effect was seen in the tamoxifen-treated cohort, indicating AIB1 to be a predictor of tamoxifen response. In systemically untreated patients, PAX2 was not a prognostic factor, nor did it modify the effect of AIB1. However, in ER-positive patients receiving tamoxifen, PAX2 appeared to be a positive prognostic factor in premenopausal patients, while a negative factor in postmenopausal. The interaction between the menopausal status and PAX2 was significant (P = 0.01).ConclusionsIn an independent cohort of low-risk premenopausal patients, we validate AIB1 as a negative prognostic factor, indicating AIB1 to be an interesting target for new anti-cancer therapies. The effect of PAX2 warrants further studies