{"id":5969,"date":"2026-10-19T09:48:16","date_gmt":"2026-10-19T09:48:16","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-birna-thorvaldsdottir\/"},"modified":"2026-10-19T09:48:16","modified_gmt":"2026-10-19T09:48:16","slug":"doktorsvorn-i-lif-og-laeknavisindum-birna-thorvaldsdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-birna-thorvaldsdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum – Birna \u00deorvaldsd\u00f3ttir"},"content":{"rendered":"
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Fimmtudaginn 21. n\u00f3vember ver Birna \u00deorvaldsd\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed l\u00edf- og l\u00e6kna-v\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: Stakst\u00e6\u00f0 \u00e1hrif og telomere-gallar \u00ed BRCA2-tengdum krabbameinum. BRCA2 related cancer, haploinsufficiency and telomere dysfunction.<\/p>\n

Andm\u00e6lendur eru dr. Katherine Nathanson, pr\u00f3fessor vi\u00f0 University of Pennsylvania \u00ed Bandar\u00edkjunum og dr. Jos Jonkers, pr\u00f3fessor vi\u00f0 The Netherlands Cancer Institute \u00ed Hollandi.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi var dr. J\u00f3runn Erla Eyfj\u00f6r\u00f0, pr\u00f3fessor emeritus vi\u00f0 L\u00e6knadeild, me\u00f0lei\u00f0beinandi var dr. Stef\u00e1n \u00de. Sigur\u00f0sson, d\u00f3sent vi\u00f0 L\u00e6knadeild. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd dr. Elizabeth Blackburn, pr\u00f3fessor, dr. J\u00f3n J\u00f3hannes J\u00f3nsson, pr\u00f3fessor og dr. Sigr\u00ed\u00f0ur Klara B\u00f6\u00f0varsd\u00f3ttir, forst\u00f6\u00f0uma\u00f0ur L\u00edfv\u00edsindaseturs.<\/p>\n

Dr. Engilbert Sigur\u00f0sson, pr\u00f3fessor og forseti L\u00e6knadeildar H\u00e1sk\u00f3la \u00cdslands, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 13:00.<\/p>\n

\u00c1grip af ranns\u00f3kn<\/strong><\/p>\n

K\u00edml\u00ednust\u00f6kkbreytingar \u00ed BRCA2 geni auka verulega l\u00edkurnar \u00e1 brj\u00f3sta- og eggjastokkakrabbameini. BRCA2 pr\u00f3teini\u00f0 er mikilv\u00e6gt til a\u00f0 vi\u00f0halda st\u00f6\u00f0ugleika erf\u00f0amengisins \u00fear sem \u00fea\u00f0 gegnir lykilhlutverki vi\u00f0 endurr\u00f6\u00f0unarvi\u00f0ger\u00f0 \u00e1 tv\u00ed\u00fe\u00e1tta brotum \u00ed DNA og ver st\u00f6\u00f0va\u00f0ar eftirmyndunarkv\u00edslar fyrir ni\u00f0urbroti. BRCA2 telst til \u00e6xlisb\u00e6ligena og almennt er gert r\u00e1\u00f0 fyrir tapi \u00e1 villiger\u00f0arsams\u00e6tu \u00feess \u00ed illkynja \u00e6xlum. Hins vegar hefur veri\u00f0 s\u00fdnt fram \u00e1 a\u00f0 \u00ed hluta krabbameina BRCA2 arfbera ver\u00f0ur ekki tap \u00e1 arfblendni sem gefur til kynna stakst\u00e6\u00f0 \u00e1hrif BRCA2. Skima\u00f0 var fyrir BRCA2 999del5 landnemast\u00f6kkbreytingunni \u00ed eggjastokkakrabbameinum og brj\u00f3stakrabbameinum \u00ed k\u00f6rlum \u00far \u00edslenska \u00fe\u00fd\u00f0inu. Tap \u00e1 arfblendni var til sta\u00f0ar \u00ed meirihluta \u00feessara \u00e6xla. Hins vegar hefur veri\u00f0 s\u00fdnt fram \u00e1 a\u00f0 tap \u00e1 arfblendni eigi s\u00e9r einungis sta\u00f0 \u00ed um helmingi brj\u00f3stakrabbameina \u00far kvenkyns arfberum. \u00deetta undirstrikar mismunandi ferla \u00ed krabbameinsmyndun milli \u00feessara h\u00f3pa og bendir til stakst\u00e6\u00f0ra \u00e1hrifa BRCA2 \u00ed brj\u00f3stvef kvenna. Gallar \u00e1 telomerum eru algengir \u00ed frumum sem tapa\u00f0 hafa BRCA2 en arfblendnar frumur eru minna rannsaka\u00f0ar. Ni\u00f0urst\u00f6\u00f0ur verkefnisins s\u00fdndu a\u00f0 styttri telomerar \u00ed bl\u00f3\u00f0i og e\u00f0lilegum brj\u00f3stavef \u00far BRCA2 arfberum tengdust l\u00e6gri greiningaraldri brj\u00f3stakrabbameins, en ekki hj\u00e1 vi\u00f0mi\u00f0unarh\u00f3pi. Stuttir telomerar geta bent til galla \u00ed vi\u00f0haldi telomera. Stuttir telomerar og miki\u00f0 magn DNA skemmda einkenndi jafnframt kirtil\u00feekjufrumur \u00ed e\u00f0lilegum brj\u00f3stavef, sem er athyglisvert fyrir \u00fe\u00e6r sakir a\u00f0 flest brj\u00f3stakrabbamein eiga uppruna \u00ed \u00feessum frumum.<\/p>\n

Abstract<\/strong><\/p>\n

Germline mutations in BRCA2 increase the risk of breast and ovarian cancer. The BRCA2 protein is involved in maintaining genomic stability through its roles in DNA double strand break repair and protection of stalled replication forks. The BRCA2 gene is considered a classical tumor suppressor gene and loss of heterozygosity (LOH) is generally assumed in\u00a0 malignant tumors. However, retention of the wild type allele is observed in a subset of tumors from mutation carriers, suggesting BRCA2 haploinsufficiency. Icelandic cohorts of ovarian cancer and male breast cancer were screened for the BRCA2 999del5 founder mutation. Locus specific LOH was found present in a large majority of tumors in both cohorts. In contrast, retention of the wild-type allele has been shown to occur in up to half of female breast tumors from BRCA2 mutation carriers. This highlights heterogeneous tumor development and\/or progression pathways between tissues and indicates tissue-specific BRCA2 haploinsufficiency in the female breast. Cells lacking BRCA2 develop telomere abnormalities. Focusing on a possible haploinsufficiency effect on telomeres in female BRCA2 mutation carriers, shorter telomere length in both blood and normal breast tissue was associated with earlier breast cancer occurrence in BRCA2 mutation carriers but not in non-carriers. Short telomeres are often indicative of dysfunctional telomere maintenance. Additionally, short telomeres and high levels of DNA damage were observed in luminal epithelial cells in normal breast tissue which is highly relevant as these are the cells from which most breast cancers arise.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Birna \u00deorvaldsd\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1989 \u00ed Reykjav\u00edk. H\u00fan lauk st\u00fadentspr\u00f3fi af n\u00e1tt\u00farufr\u00e6\u00f0ibraut Menntask\u00f3lans \u00ed Reykjav\u00edk \u00e1ri\u00f0 2009 og BS-pr\u00f3fi \u00ed l\u00edffr\u00e6\u00f0i \u00e1ri\u00f0 2013 fr\u00e1 L\u00edf- og umhverfisv\u00edsindadeild H\u00e1sk\u00f3la \u00cdslands. Birna h\u00f3f meistaran\u00e1m \u00ed l\u00edf-og l\u00e6knav\u00edsindum \u00e1ri\u00f0 2013 sem breytt var \u00ed doktorsn\u00e1m \u00e1ri\u00f0 2014. Samb\u00fdlisma\u00f0ur Birnu er Gunnar S. J\u00fal\u00edusson l\u00e6knir.<\/p>\n<\/div><\/div>","protected":false},"featured_media":1129,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2019-11-21T13:00:00+00:00","_phd_date_end":"2019-11-21T16:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Stakst\u00e6\u00f0 \u00e1hrif og telomere-gallar \u00ed BRCA2-tengdum krabbameinum. 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