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8. Localization of BRCA2 to chromosome 13Q12-13 by genetic linkage analysis
Abstracts of the 4th Nottingham International Breast Cancer Conference cycles), grade 2/3 arthralgia/myalgia PNS (17/166).
(42/166)
and grade 213
7. The yield of an intensive follow-up programme for women at increased risk for breast cancer E. J. Th. Rutgers, E. Bosnard
M. M. Mjdendaal,
J. L. Peterso, A. P.
The Netherlands Cancer InstitutelAntonl van Laeuwenhoek Huis, Arnstardam, The Netherlands The aim of this study was to determine which method and in what stage breast cancer is diagnosed in women with an increased risk for breast cancer according to an intensive control scheme. This was a retrospective study analysis of clinico-pathological data from 113 patients with breast cancer diagnosed while on periodic follow-up (semi-annual physical examination and annual mammography). Reasons for follow-up were: premalignant lesion on biopsy (atypical ductal hyperplasia, lobular carcinoma in situ): 28 patients (23%), family history (2 or more first degree relatives with breast cancer): 43 patients (38%), previous biopsy with proliferative benign lesion: 44 patients (39%). Mean follow-up time to breast cancer diagnosis was 80 months (range l-14 years; 54 patients over 5 years). At the first visit, 32 women were younger than 40 years and 43 over 60 years. During follow-up a total of 408 mammograms were performed; 78% were considered as evaluable. Malignancy was mammographically detected in 38 patients (34%); 38 patients detected an abnormality which turned out to be breast cancer. In 37 patients (32%), the tumour was detected by clinical palpation at routine physical examination. From the 75 clinically diagnosed cancers, the subsequent mammogram confirmed a suspicious lesion in 40 patients, while all the previous mammograms (usually performed - 1.5 years before) were considered to be normal. The clinical tumour size was: 5 2 cm in 47 patients (31%), > 2 cm in 33 patients (29%) and clinically occult in 23 (20%). Pathologically DCIS was found in 6 patients, a tumour 2 2 cm in 70 and > 2 cm in 23 patients. Lymph node motastases were found in 38 patients (34%): 10 patients had more than 5 positive nodes. Stage grouping according to histology was as follows: stage 0 = lo%, stage I = 41%, stage II = 36% and stage III = 1% (unknown 12%). Stages were equally divided over the 3 risk groups. After a mean follow-up time of 73 months (range 1 l-148 months) 10 patients have matastases, and 6 of these patients have died. In conclusion intensive follow-up for increased risk for breast cancer does not lead to an early detection. In our relative young group only 50% of cancers were diagnosed in a curable stage (PTle-1 PNO). Apart from regular mammography, patient awareness (i.e. breast self examination) and regular physical examination appear to play role in the detection of breast cancer.
8. Localization of BRCA2 to chromosome 13Q12-13 by genetic linkage analysis R. Wooster, J. Mangion, N. Collins, D. Ford, P. A. Daly, W. Ormiston, R. McManus, D. F. Easton, D. E. Goldgar, R. Stratton.
Institute of Cancer Research, Sutton, UK, Trinity College Medical School, Dublin, Eire Department of Medical Informatics, University of Utah, USA Following the localization of the BRCAl gene in 1990, an analysis of over 200 breast cancer families indicated that
229
the large majority of breast ovarian families were attributable to this gene, while approximately half of families with breast cancer only were apparently unlinked. The suspicion that other susceptibility genes exist was confirmed by a study of families with at least one case of male breast cancer. Of 22 families of this type, the best estimate was that none were due to BRCAI. A genome linkage search was instituted in collaboration with the University of Utah and other groups from the breast cancer linkage consortium ultimately resulting in the localization of BRCA2 to chromosome 13ql2-13. BRCA2 predisposes to early onset breast cancer with most gene carriers developing the disease prior to age 50 years. There is also a risk of ovarian cancer. Overall, this is less than the ovarian cancer risk of BRCAl, however there are certain families showing strong evidence of linkage to BRCA2 in which there are several cases of ovarian cancer. This may indicate the existence of BRCAZ allelic variants which confer differing risks of ovarian cancer. The risk of male breast cancer is considerably higher than in families linked to BRCAl. Previous loss of heterozygosity (LOH) studies in sporadic breast and ovarian cancer suggested that the 13ql2-13 region may harbour a tumour suppressor gene which is distinct from RBI. These observations have been confirmed on the basis of occasional LOH breakpoints between RBI and the BRCAZ region. LOH studies using tumours from BRCAZ families demonstrate that it is always the wild type allele that is lost in the cancer, a finding consistent with the two hit hypothesis and suggesting that BRCA2 is a tumour suppressor gene.
9. Absence of mutation in p21 in breast cancers with wild-type ~53 A. A. Evans, J. N. Primrose,
G. T. Royle,
T. R. Crook
Department of Surgery, Southampton General Hospital, Institute of Cancer Research, Sutton, UK P21 Waf-I, a potent inhibitor of cyclin-dependent kinases, has recently been identified as a downstream effector of ~53 function. This observation raises the possibility that its loss of function of Waf-I, via allele loss and/or mutation, may represent a molecular mechanism whereby tumours which retain and express wild-type ~53 evade the Gl-S checkpoint and apoptosisregulating functions of ~53. We have analyzed the structure and expression of Waf--I in a series of primary breast tumours of varying ~53 status. In preliminary studies the ~53 status of tumours and matched normal tissue was established using single strand conformation polymorphism (SSCP) analysis, cloning and DNA sequencing. Total cellular RNA was isolated from the same series of tumours and matched normal tissue by guanidinium/phenol extraction and was subjected to reverse transcription (RT). The entire Waf--l coding sequence was then amplified by polymerase chain reaction (PCR). A portion of the copied DNA was cloned into plasmid vectors and sequenced. A further aliquot of the PCR reaction was analyzed by agarose gel electrophoresis with a co-amplified control cDNA, to obtain a semi-quantitative estimate of Waf--I expression. Of 12 primary breast carcinomas, ~53 mutation was detected in three. Expression of Waf-I, as assessed by semi-quantitative RT-PCR, was markedly higher in the tumours with wild-type ~53 than those with mutations. Changes in the Waf-Z coding sequence were not detectable in any of the tumours, irrespective of ~53 status. These data are consistent with the transcriptional upregulation of Waf--1by ~53, but imply that loss of function mutations in Waf--l are rare in breast cancer. The subversion of p53-mediated tumour suppression by tumours which retain and express the wild-type gene must involve alternative mechanisms.
(42/166)
and grade 213
7. The yield of an intensive follow-up programme for women at increased risk for breast cancer E. J. Th. Rutgers, E. Bosnard
M. M. Mjdendaal,
J. L. Peterso, A. P.
The Netherlands Cancer InstitutelAntonl van Laeuwenhoek Huis, Arnstardam, The Netherlands The aim of this study was to determine which method and in what stage breast cancer is diagnosed in women with an increased risk for breast cancer according to an intensive control scheme. This was a retrospective study analysis of clinico-pathological data from 113 patients with breast cancer diagnosed while on periodic follow-up (semi-annual physical examination and annual mammography). Reasons for follow-up were: premalignant lesion on biopsy (atypical ductal hyperplasia, lobular carcinoma in situ): 28 patients (23%), family history (2 or more first degree relatives with breast cancer): 43 patients (38%), previous biopsy with proliferative benign lesion: 44 patients (39%). Mean follow-up time to breast cancer diagnosis was 80 months (range l-14 years; 54 patients over 5 years). At the first visit, 32 women were younger than 40 years and 43 over 60 years. During follow-up a total of 408 mammograms were performed; 78% were considered as evaluable. Malignancy was mammographically detected in 38 patients (34%); 38 patients detected an abnormality which turned out to be breast cancer. In 37 patients (32%), the tumour was detected by clinical palpation at routine physical examination. From the 75 clinically diagnosed cancers, the subsequent mammogram confirmed a suspicious lesion in 40 patients, while all the previous mammograms (usually performed - 1.5 years before) were considered to be normal. The clinical tumour size was: 5 2 cm in 47 patients (31%), > 2 cm in 33 patients (29%) and clinically occult in 23 (20%). Pathologically DCIS was found in 6 patients, a tumour 2 2 cm in 70 and > 2 cm in 23 patients. Lymph node motastases were found in 38 patients (34%): 10 patients had more than 5 positive nodes. Stage grouping according to histology was as follows: stage 0 = lo%, stage I = 41%, stage II = 36% and stage III = 1% (unknown 12%). Stages were equally divided over the 3 risk groups. After a mean follow-up time of 73 months (range 1 l-148 months) 10 patients have matastases, and 6 of these patients have died. In conclusion intensive follow-up for increased risk for breast cancer does not lead to an early detection. In our relative young group only 50% of cancers were diagnosed in a curable stage (PTle-1 PNO). Apart from regular mammography, patient awareness (i.e. breast self examination) and regular physical examination appear to play role in the detection of breast cancer.
8. Localization of BRCA2 to chromosome 13Q12-13 by genetic linkage analysis R. Wooster, J. Mangion, N. Collins, D. Ford, P. A. Daly, W. Ormiston, R. McManus, D. F. Easton, D. E. Goldgar, R. Stratton.
Institute of Cancer Research, Sutton, UK, Trinity College Medical School, Dublin, Eire Department of Medical Informatics, University of Utah, USA Following the localization of the BRCAl gene in 1990, an analysis of over 200 breast cancer families indicated that
229
the large majority of breast ovarian families were attributable to this gene, while approximately half of families with breast cancer only were apparently unlinked. The suspicion that other susceptibility genes exist was confirmed by a study of families with at least one case of male breast cancer. Of 22 families of this type, the best estimate was that none were due to BRCAI. A genome linkage search was instituted in collaboration with the University of Utah and other groups from the breast cancer linkage consortium ultimately resulting in the localization of BRCA2 to chromosome 13ql2-13. BRCA2 predisposes to early onset breast cancer with most gene carriers developing the disease prior to age 50 years. There is also a risk of ovarian cancer. Overall, this is less than the ovarian cancer risk of BRCAl, however there are certain families showing strong evidence of linkage to BRCA2 in which there are several cases of ovarian cancer. This may indicate the existence of BRCAZ allelic variants which confer differing risks of ovarian cancer. The risk of male breast cancer is considerably higher than in families linked to BRCAl. Previous loss of heterozygosity (LOH) studies in sporadic breast and ovarian cancer suggested that the 13ql2-13 region may harbour a tumour suppressor gene which is distinct from RBI. These observations have been confirmed on the basis of occasional LOH breakpoints between RBI and the BRCAZ region. LOH studies using tumours from BRCAZ families demonstrate that it is always the wild type allele that is lost in the cancer, a finding consistent with the two hit hypothesis and suggesting that BRCA2 is a tumour suppressor gene.
9. Absence of mutation in p21 in breast cancers with wild-type ~53 A. A. Evans, J. N. Primrose,
G. T. Royle,
T. R. Crook
Department of Surgery, Southampton General Hospital, Institute of Cancer Research, Sutton, UK P21 Waf-I, a potent inhibitor of cyclin-dependent kinases, has recently been identified as a downstream effector of ~53 function. This observation raises the possibility that its loss of function of Waf-I, via allele loss and/or mutation, may represent a molecular mechanism whereby tumours which retain and express wild-type ~53 evade the Gl-S checkpoint and apoptosisregulating functions of ~53. We have analyzed the structure and expression of Waf--I in a series of primary breast tumours of varying ~53 status. In preliminary studies the ~53 status of tumours and matched normal tissue was established using single strand conformation polymorphism (SSCP) analysis, cloning and DNA sequencing. Total cellular RNA was isolated from the same series of tumours and matched normal tissue by guanidinium/phenol extraction and was subjected to reverse transcription (RT). The entire Waf--l coding sequence was then amplified by polymerase chain reaction (PCR). A portion of the copied DNA was cloned into plasmid vectors and sequenced. A further aliquot of the PCR reaction was analyzed by agarose gel electrophoresis with a co-amplified control cDNA, to obtain a semi-quantitative estimate of Waf--I expression. Of 12 primary breast carcinomas, ~53 mutation was detected in three. Expression of Waf-I, as assessed by semi-quantitative RT-PCR, was markedly higher in the tumours with wild-type ~53 than those with mutations. Changes in the Waf-Z coding sequence were not detectable in any of the tumours, irrespective of ~53 status. These data are consistent with the transcriptional upregulation of Waf--1by ~53, but imply that loss of function mutations in Waf--l are rare in breast cancer. The subversion of p53-mediated tumour suppression by tumours which retain and express the wild-type gene must involve alternative mechanisms.