Mapping loss of heterozygosity at chromosome 13q: Loss at 13q12-q13 is associated with breast tumour progression and poor prognosis

• Main Authors: Sigurður Ingvarsson 1956-, Guðný Eiriksdóttir 1950-, Guðrún Jóhannesdóttir 1957-, Inga Birna Björnsdóttir 1958-, Jón Gunnlaugur Jónasson 1956-, Bjarni A. Agnarsson 1952-, Jónas Hallgrímsson 1931-, Júlíus Guðmundsson 1968-, Valgarður Egilsson 1940-, Helgi Sigurðsson 1953-, Rósa Björk Barkardóttir 1958-
• Other Authors: Háskóli Íslands
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1998
• Subjects: Brjóstakrabbamein; Iceland
• Online Access: http://hdl.handle.net/1946/20808

Several chromosome regions exhibit loss of heterozygosity (LOH) in human breast carcinoma and are thought to harbour tumour suppressor genes (TSG). At chromosome 13q, two TSGs have been identified, RB1 at 13q14 and BRCA2 at 13q12-q13. In this study, 139 sporadic breast tumours were analysed with 18 polymorphic microsatellite markers for detailed mapping of LOH at chromosome 13q and evaluation of an association with known progression factors. LOH with at least one marker was observed in 71 (51%) of the tumours analysed. The deletion mapping indicated three LOH target regions, 13q12-q13, 13q14 and 13q31-q34. LOH at chromosome 13q12-q13 was associated with low progesterone receptor content, a high S phase fraction and aneuploidy. Multivariate analysis adjusting for lymph node involvement and S phase fraction showed that patients with tumours exhibiting LOH at 13q12-q13 have a 3-4-fold increased risk of recurrence and death compared with other patients. Our results suggest there are at least three separate LOH target regions at chromosome 13q and inactivation of one or more genes at chromosome 13q12-q13 results in poor prognosis for breast cancer patients. This work was financially supported by the Research Fund of the University of Iceland, the Nordic Cancer Union, Icelandic Cancer Society, Memorial Fund of Bergthora Magnusdottir and Jakob B. Bjarnason, the Research Council of Iceland and the Science Fund of the University Hospital of Iceland.