Utilisation of prophylactic mastectomy in 10 European centres

Increasingly women at high risk of breast cancer are opting for prophylactic surgery to reduce their risks. Data from 10 European centres that offer a risk counselling and screening service to women at risk show different approaches to the option of preventive surgery, although most centres adhere to a protocol including at least two risk counselling sessions and a psychological assessment. Thus far the combined centres have data on 174 women who have undergone prophylactic mastectomy with in excess of 400 women years of follow up. Operations were carried out on women with lifetime risks of 25-80%, with an average annual expected incidence rate of 1% per women. No breast cancers have occurred in this cohort. Long term follow up on an extended group of women will be necessary to truly address the risk of subsequent breast cancer and the psychological sequelae.

Genetics of cancer: current knowledge and future possibilities

For many years there has been scepticism among clinicians and cancer epidemiologists as to whether cancer was a genetic disease or could be hereditary. It is only in the last 10 years that developments in molecular biology have proven the hereditary nature of a small proportion of certain common cancers. That cancer is now indisputably 'genetic' at the cellular level is beyond dispute.

Differential diagnosis of type 2 neurofibromatosis: molecular discrimination of NF2 and sporadic vestibular schwannomas

Patients who present with unilateral vestibular schwannomas either at a young age or with additional features of type 2 neurofibromatosis (NF2) are at risk of developing bilateral disease and transmitting a risk of neurogenic tumours to their offspring. We have identified 15 patients from a series of 537 with unilateral vestibular schwannomas who also had one or more of the following: other tumours (10/15), features of NF2 (3/15), or a family history of neurogenic tumours (5/15). No germline NF2 mutations were detected and in 7/9 cases where tumour material was available for analysis a germline mutation in the NF2 gene has been excluded. Although a possibility of gonosomal mosaicism still exists, exclusion tests for the offspring are now possible. We suggest a general strategy, based on analysis of tumour DNA, for distinguishing sporadic and familial cases of tumours caused by two hit mechanisms. Application of this strategy suggests that most instances of unilateral vestibular schwannoma which do not fulfil criteria for NF2 represent chance occurrences.

Current policies for surveillance and management in women at risk of breast and ovarian cancer: a survey among 16 European family cancer clinics. European Familial Breast Cancer Collaborative Group

The recent isolation of breast cancer predisposing genes (BRCA1 and BRCA2) allows the identification of carriers within affected families. These carriers have a 50-85% risk of developing breast or ovarian cancer and need careful follow-up. The purpose of this study was to evaluate the management and screening protocols implemented in high risk families at various family cancer clinics in Europe. A questionnaire was mailed to the members of the European Familial Breast Cancer Collaborative Group (n = 30) requesting information on the following issues: indication for surveillance of breasts and ovaries, the recommended protocol, coordination of the screening examination, prophylactic surgery, the specific management of breast cancer in a mutation carrier and the use of oestrogen. 16 centres from nine countries responded. Most centres recommend surveillance of the breasts if the lifetime risk exceeds 15-20%. The surveillance protocol that is generally advised comprises monthly self breast examination, examination by a specialist every 6 months and annual mammography, all starting from an age between 25 and 35 years. Surveillance of the ovaries is recommended in BRCA1 and BRCA2-mutation carriers, in members from breast/ovarian cancer families and in some centres in 'breast cancer only' families with an early onset of breast cancer. The recommended protocol includes gynaecological examination, sonography and estimation of CA-125 at yearly intervals starting from the age 30-35 years. Prophylactic mastectomy is considered for proven mutation carriers in some centres. Most centres consider prophylactic oophorectomy in mutation carriers and some centres also consider it for members of breast/ovarian cancer families. This survey provides insight into the guidelines for surveillance and management of familial breast cancer used at various family cancer clinics in Europe; this insight may contribute to the appropriate management of these high risk women. It should be emphasised that most recommendations are based on experts' opinion rather than on any specific studies.

Helicobacter pylori cagA status and s and m alleles of vacA in isolates from individuals with a variety of H. pylori-associated gastric diseases

The cagA gene was detected in 100% of 16 Helicobacter pylori isolates from patients with gastric carcinoma versus 78% of 18 isolates from patients with duodenal ulcers (P = 0.344) and only 64% of 22 isolates from patients with gastritis only (P = 0.005) in Brazil. Also, there was a significant association between isolation of cagA+ s1-type vacA H. pylori in cases of stomach cancer and ulcers as opposed to cases of gastritis only (P = 0.004), but this was not true in Houston (P = 0.238), where 94% of all isolates were cagA+.

A novel TP53 splicing mutation in a Li-Fraumeni syndrome family: a patient with Wilms' tumour is not a mutation carrier

We report a Li-Fraumeni syndrome family in which we have detected a splice acceptor mutation in intron 3 of TP53. The mutation affects one of the invariant residues at the splice acceptor site, as a result of which two aberrant transcripts are produced. A child with Wilms' tumour aged 3 years in this family was shown not to be a mutation carrier.

Cancer phenotype correlates with constitutional TP53 genotype in families with the Li-Fraumeni syndrome

The Li-Fraumeni cancer predisposition syndrome is associated with germline TP53 mutations in the majority of families. We have investigated cancer incidence in 34 Li-Fraumeni families, according to their constitutional TP53 mutation status. Families with germline missense mutations in the core DNA binding domain showed a more highly penetrant cancer phenotype than families with other TP53 mutations or no mutation. Cancer phenotype in families carrying such mutations was characterized by a higher cancer incidence and earlier ages at diagnosis, especially of breast cancer and brain tumours, compared with families carrying protein truncating or other inactivating mutations (P=0.03 for all cancers, P=0.006 for breast cancers, P=0.05 for brain tumours). Proband cancers showed significantly younger ages at diagnosis in those with missense mutations in the DNA binding domain than in those with protein inactivating mutations (P=0.031). In individuals with the former type of mutation, there was a significantly lower proportion of tumours which showed loss of the wild-type TP53 allele (P=0.004). These results are consistent with observations in experimental systems which demonstrate that certain mutations exhibit gain of function and/or dominant-negative properties. Our results support an enhanced oncogenic potential for such mutations in human populations.

Men in breast cancer families: a preliminary qualitative study of awareness and experience

In inherited forms of breast cancer, attention in clinical genetics services has focused on women because they are most at risk of developing cancer. Men at risk of transmitting a predisposing gene mutation are less likely to have a genetic test than the women in these families. This preliminary study investigates the perspective of the brothers of women with familial breast cancer and is based on qualitative analysis of 22 semistructured interviews using an attenuated form of Grounded Theory. There is an awareness among these men (without having had genetic counselling) that the breast cancer in their families is inherited. Some of them harbour fear of developing cancer themselves and many are concerned that their daughters might develop breast cancer. Some appeared to use avoidance as a coping strategy. The men were very often excluded from family conversations about breast cancer. Implications for the provision of genetic counselling for these families are discussed.

Somatic mosaicism: a common cause of classic disease in tumor-prone syndromes? Lessons from type 2 neurofibromatosis

Blood samples from 125 families with classic type 2 neurofibromatosis with bilateral vestibular schwannomas were analyzed for mutations in the NF2 gene. Causative mutations were identified in 52 families. In five families, the first affected individual in the family (the index case) was a mosaic for a disease-causing mutation. Only one of nine children from the three mosaic cases with children are affected. Four of these nine children inherited the allele associated with the disease-causing mutation yet did not inherit the mutation. NF2 mutations were identified in only 27/79 (34%) of sporadic cases, compared with 25/46 (54%) of familial cases (P<.05). In 48 families in which a mutation has not been identified, the index cases have had 125 children, of whom only 29 are affected with NF2 and of whom only a further 21 cases would be predicted to be affected by use of life curves. The 50/125 (40%) of cases is significantly less than the 50% expected eventually to develop NF2 (P<.05). Somatic mosaicism is likely to be a common cause of classic NF2 and may well account for a low detection rate for mutations in sporadic cases. Degrees of gonosomal mosaicism mean that recurrence risks may well be <50% in the index case when a mutation is not identified in lymphocyte DNA.

False family history of breast cancer in the family cancer clinic

AIMS

Awareness of hereditary breast and ovarian cancer in both the general public and the medical profession is increasing. Individuals who may be at risk on the basis of a family history are requesting risk determination and appropriate management in a variety of settings. Risk determination relies largely on pedigree analysis and epidemiological data.

METHODS

We describe five individuals presenting in the family cancer or genetic counselling clinic where a factitious family or personal history led to erroneous risk estimation. Common factors in these families are a history of benign breast disease, poor communication within families, long survival with early onset or bilateral disease, a lack of detailed knowledge of the illness and treatment in close relatives and inconsistencies in the history in repeated consultations.

Genetic and functional studies of a germline TP53 splicing mutation in a Li-Fraumeni-like family

We report an extensive Li-Fraumeni-like family in which there is an unusual spectrum of tumours at relatively late onset. A germline TP53 splice donor mutation in exon 4 is present in all affected family members available for testing. The mutation abolishes correct splicing of intron 4 and techniques of RT-PCR have identified three different aberrant transcripts from the mutant TP53 allele. Using the yeast functional assay to analyse transcripts in cells from a number of family members with the mutant allele, TP53 appears wild-type. Functional studies have been carried out on cells from patients with and without cancer who carry the germline mutation, and on cells from unaffected individuals from the same family who do not carry the mutation. Using a number of functional endpoints known to distinguish between cells carrying mutant or wild-type TP53 alleles, we were unable to discriminate normal (wt/wt) from heterozygous (wt/mut) cells by lymphocyte apoptosis and fibroblast survival following low dose rate ionising radiation exposure. However germline mutation carriers show increased sensitivity to radiation-induced chromosome damage in the G2 phase of the cell cycle, and decreased transient and permanent G1 arrest. These studies demonstrate the importance of fully characterising the effects of TP53 germline mutations, and may explain some of the phenotypic features of this family.

Genotype/phenotype correlations in type 2 neurofibromatosis (NF2): evidence for more severe disease associated with truncating mutations

Blood samples from 125 unrelated families with classical type 2 neurofibromatosis (NF2) with bilateral vestibular schwannomas have been analysed for mutations in the NF2 gene. A further 17 families fulfilling modified criteria for NF2 have also been analysed. Causative mutations have been identified in 54 (43%) classical families and six (35%) of those fulfilling modified criteria. Forty-two cases from 38 families with truncating mutations had an average age at onset of symptoms of 19 years and diagnosis at 22.4 years. Fifty-one cases from 16 families with splice site mutations (15 from six), missense mutations (18 from six), and large deletions (18 from five) had an average age of onset of 27.8 years and at diagnosis of 33.4 years. Subjects with truncating mutations were significantly more likely to have symptoms before 20 years of age (p<0.001) and to develop at least two symptomatic CNS tumours in addition to vestibular schwannoma before 30 years (p<0.001). There were also significantly fewer multigenerational families with truncating mutations. Four further truncating mutations were in mosaic form and were associated with milder disease than other similar mutations. This large study has confirmed the previous impression that truncating mutations are associated with severe disease, but caution has to be exercised in using mutation type to predict disease course.

Screening by mammography, women with a family history of breast cancer

The aim of this study was to describe the experience of screening women under the age of 50 years with a family history of breast cancer. 1259 women attended the Family History Clinic in Manchester for their first and subsequent consultations between 30 September 1992 and 30 April 1997. All women were under the age of 50 years at the initial consultation and had a lifetime risk of breast cancer of 1 in 6 or greater. Seven prevalent, seven incident and two interval cancers were detected. The number of invasive cancers expected to occur if this high risk population had not been screened was 8.45 (in 2722 person years at risk). 12 invasive cancers were detected, giving a ratio of 1.42 (95% confidence interval 0.73-2.48). The overall cancer detection rates in this young, at risk population were similar to those in older women in the National Health Service Breast Screening Programme. The number of cancers detected in the study was greater than expected in this population. As the numbers were small, a national trial needs to be undertaken to confirm these results and to determine the long term effects of screening.

Diversity in the variable region of Helicobacter pylori cagA gene involves more than simple repetition of a 102-nucleotide sequence

CagA, a product of cytotoxin-associated gene A cagA, is an important virulence-related antigen of Helicobacter pylori (HP). CagA varies in size from 128 kDa to about 140 kDa and this variation is believed to be generated by a 102-nucleotide (NT) repeat sequence in the so-called variable region of cagA. However, this explanation has not previously been tested by comparing the NT sequences of cagA derived from a number of different isolates of HP. In this study we first compared the size of PCR products obtained from 54 different isolates of HP with oligonucleotide primers designed to amplify a cagA fragment predicted to be at least 1059 NT, including the variable region of the gene. As expected, the size of the PCR products varied considerable, from 1110 to 1822 NT, but the majority (50 of 54) measured 1335 NT or less. The deduced amino acid (AA) sequences of 9 representative amplicons and 4 other known sequences were compared with the following result: Within the variable region of cagA there are actually two adjacent variable regions, which we label as proximal and distal. The proximal-variable region of CagA extends from a motif of 4 to 6 asparagine residues to a 7-AA repeat sequence (KIDQLNQ); the distal-variable region is confined between KIDQLNQ and a well-conserved duplicate, KIDNLNQ. Despite these shared features CagA of every HP strain examined to date has a variable region with a unique AA sequence.

An evaluation of common breast cancer gene mutations in a population of Ashkenazi Jews

OBJECTIVES

In view of the recent reports of recurrent mutations in BRCA1 and BRCA2 in the Ashkenazi Jewish population, we have undertaken to assess the frequency of these mutations in this population attending for genetic counselling and risk assessment of familial breast cancer.

DESIGN

Mutation screening for the 185delAG and the 5382insC mutations in BRCA1 and the 6174delT mutation in BRCA2 was performed on DNA samples from either subjects affected by breast or ovarian cancer or obligate gene carriers. The likelihood of the cancers being hereditary in each family was calculated.

SUBJECTS

Blood samples were obtained from 26 affected subjects or obligate gene carriers from 23 Ashkenazi Jewish families, all with a history of either early onset breast or ovarian cancers, or multiple cases of breast or ovarian cancer.

RESULTS

Twelve mutations have been identified in the 23 families (52%) of which eight (67%) were the 185delAG mutation, three (25%) were the 6174delT mutation, and one (8%) was the 5382insC mutation. While the majority of these mutations were identified in families with a greater than 50% probability of being hereditary under the CASH segregation model, three mutations were identified in families with a 35% or less probability.

CONCLUSIONS

Genetic screening of the recurrent mutations in Ashkenazi Jewish families will lead to the availability of predictive testing in a reasonably large proportion, even if the family history of breast/ovarian cancer is not particularly strong. In our view it is possible to reassure high risk unaffected members of these families, if the screening is negative for these mutations, even if a sample from an affected member of the family is unavailable for previous screening.

Misleading linkage results in an NF2 presymptomatic test owing to mosaicism

A two generation family with neurofibromatosis type 2 (NF2) is presented in which a family member requested presymptomatic molecular diagnosis. Since the consultand's mother had clinically well defined NF2, he was quoted to be at 50% risk of carrying an NF2 mutation. Mutation screening in the mother did not show the causative mutation and, consequently, presymptomatic testing was based on linkage analysis. This showed that the consultand carried the high risk chromosome 22. Subsequent mutation screening of his clinically affected sister showed a nonsense mutation, R262X in exon 8 of the NF2 gene. The mother turned out to be a mosaic for R262X; the son had not inherited the mutation. Mosaicism may be a common mechanism in NF2 and other autosomal dominant diseases with a high new mutation rate. This may be one explanation for a difference in expression in generations. Caution has to be exercised when giving results based on linkage tests which imply a very high risk to people in the second generation.

Incidence of hereditary non-polyposis colorectal cancer in a population-based study of 1137 consecutive cases of colorectal cancer

BACKGROUND

Previous reports have indicated that 5-13 per cent of colorectal cancer is hereditary. However, the proportion of cases arising as a result of mutations in the hereditary non-polyposis colorectal cancer (HNPCC) genes remains to be determined.

METHODS

This study is a part prospective, part retrospective review of all cases of colorectal cancer from a district hospital over 14 years. Some 1137 consecutive patients with colorectal cancer were questioned about their family history of cancer and details were logged on a database. For the past 4 years each case has been re-evaluated where possible.

RESULTS

Some 118 patients indicated initially that they had a first-degree relative with colorectal cancer, but on re-evaluation there were significant discrepancies. Only three cases (0.3 per cent) occurred in families which strictly fulfilled the criteria for HNPCC and there were no cases of familial adenomatous polyposis. A total of 16 patients (1.4 per cent) fulfilled looser criteria for HNPCC.

CONCLUSION

This population-based study has shown a lower frequency of familial bowel cancer than previous studies and may reflect a lower incidence of inherited mutations in the HNPCC DNA mismatch repair genes than is currently accepted.

Uptake of genetic testing for cancer predisposition

Although there has been much debate about the uptake and effects of predictive testing for common cancers, such as breast and colon cancer, little has been published on the more classical tumour predisposing conditions, such as von Hippel-Lindau disease and familial adenomatous polyposis. Since 1990 the genetics departments in Manchester and Cambridge have had a genetic register for cancer predisposing syndromes and presymptomatic testing for these conditions has been offered once this has become possible. To investigate the factors that might influence uptake of genetic testing in familial cancer syndromes we have reviewed our experience. Demand for predictive testing has generally been high, but men had a lower uptake (77%) than a comparable group of women (93%) (p < 0.01).

A system for enabling blind people to identify landmarks: the sound buoy

This paper describes a set of low-cost sound beacons. The paper introduces the problem area that motivated the work, considers alternative solutions and describes the radio triggered solution adopted. The paper discusses further developments to make the system suitable for indoor as well as external use.

Germ-line mutations of TP53 in Li-Fraumeni families: an extended study of 39 families

We have previously reported on the analysis of TP53 coding mutations in 12 classic Li-Fraumeni syndrome (LFS) families plus 9 families that were Li-Fraumeni-like (LFL) families (J. M. Birch et al., Cancer Res., 54: 1298-1304, 1994). Mutations were found in 6 of 12 LFS families and in 1 of 9 LFL families. We have now extended these studies to include an additional nine LFS and nine LFL families, and TP53 mutations have been detected in eight of nine LFS families and in three of nine LFL families. Six of the new mutations described here are the same as those previously identified in other Li-Fraumeni families and are missense mutations at codons 245, 248, and 273 (in two families); a nonsense mutation at codon 209; and a mutation at the splice donor site in exon 4. The other five mutations are novel germ-line mutations and include missense mutations at codons 136 and 344, a 2-bp deletion within codon 191, a splice acceptor mutation in intron 3, and a 167-bp deletion of part of exon 1 and intron 1. In addition, we have detected a codon 175 mutation in a family previously reported as TP53 negative. To summarize all of the data from the families we have studied in this and our previous report (J. M. Birch et al., Cancer Res., 54: 1298-1304, 1994), mutations have been detected in 15 of 21 LFS families (71%) and in 4 of 18 LFL families (22%). These figures are somewhat higher than those previously reported by us and others for the frequency of TP53 mutations in LFS and LFL families. This could reflect our analysis of all 11 exons of TP53, including noncoding regions, as well as the use of direct sequencing rather than other less-sensitive mutation detection methods.

Carbohydrate binding specificity of the neutrophil-activating protein of Helicobacter pylori

The possible interaction of the neutrophil-activating protein of Helicobacter pylori with target cell glycoconjugates was investigated by the binding of 125I-labeled recombinant protein to glycosphingolipids from human neutrophils in solid phase assays. Thereby, a distinct binding of the neutrophil-activating protein to four bands in the acid glycosphingolipid fraction from human neutrophils was detected, whereas no binding to the non-acid glycosphingolipids or polyglycosyl ceramides from these cells was obtained. When using glycosphingolipids not present in the cell membrane of human neutrophils, it was found that the neutrophil-activating protein also bound to sulfated glycosphingolipids as sulfatide and sulfated gangliotetraosyl ceramide. Comparison of the binding preferences of the protein to reference glycosphingolipids from other sources suggested that in human granulocytes, the neutrophil-activating protein of H. pylori preferentially recognizes glycoconjugates with a terminally unsubstituted NeuAcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta sequence.

Tc-99m-HMPAO white blood cell scan for diagnosis of acute appendicitis in patients with equivocal clinical presentation

OBJECTIVE

The authors' goal was to evaluate the accuracy of Technetium 99m-HMPAO-labeled leukocyte imaging for screening patients with atypically presenting appendicitis and to determine how availability of this test affected practice patterns of surgeons at the authors' medical center.

SUMMARY BACKGROUND DATA

Appendicitis can be difficult to diagnose and in equivocal cases usually requires inpatient observation. The delay may increase morbidity and costs. A test that rules out acute appendicitis could be cost effective if it allowed early discharge from the emergency department. Previously, there have been no simple, rapid, accurate noninvasive methods for improving diagnostic accuracy in patients with equivocal presentations of appendicitis.

METHODS

Patients referred to rule out appendicitis were analyzed. Patients were imaged up to 3 hours after injection of 10-mCi 99mTc-HMPAO-labeled autologous leukocytes (Tc-WBC), and when the scans became positive, imaging was terminated and the requesting physician notified of the results. Diagnostic accuracy was established by surgical and histopathologic findings or by absence of symptoms after 1 month clinical follow-up. The source of referral, hospital length of stay, disposition of patients, and ancillary tests (ultrasound, computed tomographic scan, and barium enema) were analyzed.

RESULTS

One hundred twenty-four patients were studied from November 1991 through December 1995. Fifty-eight percent of positive scans showed uptake within 1 hour of injection and 73% by 2 hours. The Tc-WBC scan correctly identified an inflammatory source of abdominal pain in 65 of 66 cases (sensitivity = 98%) and was correctly negative in 55 of 58 cases (specificity = 95%). The scan correctly diagnosed appendicitis in 50 of 51 cases (sensitivity = 98%) and correctly excluded appendicitis in 62 of 73 cases (specificity = 85%). Outpatient referrals increased from 38% to 87%. In those patients with negativescans, inpatient observation, number of adjunctive tests, and length of stay decreased significantly.

CONCLUSIONS

The high sensitivity and negative predictive value of Tc-WBC imaging may permit patients to be screened and discharged from the emergency department. Focally positive scans often indicate disease requiring operation but not in all cases. The Tc-WBC imaging reduced the negative laparotomy rate to 3.9% while reducing admission rates and hospital length of stay.

Physical localisation of the breakpoints of a constitutional translocation t(5;6)(q21;q21) in a child with bilateral Wilms' tumour

A 6 month old boy presented with bilateral Wilms' tumour. Cytogenetic analysis of the lymphocytes from the patient showed a de novo balanced translocation t(5;6)(q21;q21), which was also present in the tumour material as the sole cytogenetic abnormality. To facilitate the identification of the translocation breakpoints, we have established a lymphoblastoid cell line (MA214L) from the patient which maintains the translocation in culture. We have used Genethon microsatellite markers as sequence tagged sites (STSs) to isolate yeast artificial chromosome (YAC) clones to 5q and 6q from human genomic libraries. Using fluorescence in situ hybridisation (FISH) on metaphase preparations of MA214L, we have physically defined the translocation breakpoints between YAC clones on each chromosome arm. The genetic distance separating the flanking YACs on 6q21 is 3 cM, while that on 5q21 is 4 cM. To date this is the first report of these chromosomal regions being implicated in Wilms' tumourigenesis.

Spinal and cutaneous schwannomatosis is a variant form of type 2 neurofibromatosis: a clinical and molecular study

OBJECTIVE

To delineate the clinical phenotype, molecular basis, and implications for screening in patients and families with multiple schwannomas not generally involving the cranium.

METHODS

As part of a United Kingdom clinical and genetic study of type 2 neurofibromatosis (NF2) patients and families with multiple schwannomas who do not fulfil diagnostic criteria for NF2 have been identified. The clinical phenotype was studied in the extended families and molecular analysis was carried out at the NF2 gene locus on chromosome 22.

RESULTS

Patterns of inheritance in five families with schwannomatosis are consistent with inheritance of an autosomal dominant gene. The consistency of phenotype, with relative sparing of the cranium, is constant in these families. However, families which initially seem to be indicative of schwannomatosis may develop into classic NF2 as shown by a sixth family. Many of the tumours found in these families were referred to as "neurofibroma" when they were clearly schwannomas. This difference in classification has major implications for the relative risk of each particular type of neurofibromatosis and neuropathological review may be important in some cases. Genetic linkage analysis in the two largest families is entirely consistent with primary involvement of the NF2 gene.

CONCLUSIONS

Variant forms of neurofibromatosis have presented a dilemma in classification and determination of recurrence risks in families. Previous reports have suggested that schwannomatosis is a sporadic non-hereditary condition. Patients with multiple schwannomas are likely to have a variant form of NF2 and up to a 50% risk of passing on a gene predisposing to multiple schwannoma.