Abstract P3-03-01: Clinical utility of finding pathogenic mutations beyond BRCA1/2 in breast cancer patients

Background

The clinical utility of germline genetic testing for BRCA1 and BRCA2 has long been established. However, management recommendations for pathogenic variants in other genes, typically included in multigene panels, have only recently been included in consensus guidelines for HBOC. The clinician actions implemented for findings in these genes, and patient follow-up, are not yet well studied. We report interim results from a multi-site study of clinical actions undertaken in patients presenting with HBOC and carrying a pathogenic germline mutation in cancer risk genes other than BRCA1/2.

Methods

We retrospectively examined a cohort of patients with a personal history of HBOC who had been referred for hereditary cancer multigene testing from three major academic medical centers. For patients with pathogenic findings in a non-BRCA1/2 cancer risk gene, ordering clinicians completed a short case report form describing the clinical actions taken in response to the genetic test result, and patient follow-up. Some patients were lost to follow-up and answers of “unknown” were permitted. Genes with positive findings included CHEK2, PALB2, ATM, MUTYH, RAD51C, TP53, MSH6, RAD50, APC, BARD1, BRIP1, MSH2, NF1, NBN, PMS2, and PTEN. Case report forms were available for 77 patients as of our cut off date, and these data were de-identified and summarized for this interim report. Additional cases continue to accrue in this ongoing study.

Results

In 57% (44/77) of cases, clinicians reported that counseling and/or clinical management recommendations were changed in response to the genetic test findings. Management changes included modification of imaging surveillance (38%), considered or recommended surgical prophylaxis (12%), modified surgical plan for an existing malignancy (5%), and for one patient each: inclusion in a research trial for PARP inhibitors, modification of colonoscopy schedule, and screening for cancers other than existing malignancy. Clinicians indicated that genetic test results changed management in 48% of patients, did not change management in 29%, and had unknown impact for 23%.

Clinicians also reported that counseling and/or management for the patients' family members was changed in 67% (52/77) of cases, including family variant testing. 27% (21/77) of the patient families had cascade genetic testing, and one or more new carriers were identified in 47% (10) of the tested families. In 58% of cases, the impact of management recommendations on family members was unknown as of the case report date.

Conclusions

Pathogenic variants in non-BRCA genes are present in about 3-11% of patients with a history of HBOC. This study suggests that genetic test results in cancer genes beyond BRCA1/2 changed clinical management for a majority of patients and their family members, led to identification of new carriers, and directly impacted treatment decisions. In almost half of these patients, genetic test results impacted their health outcome, including those reported to be disease free after undergoing interventional or prophylactic surgery informed by their genetic variant. More research is needed to improve the implementation of genetic testing based management recommendations for patients and their family members.

Citation Format: Esplin ED, Michalski S, Yang S, Hampel H, Jeter J, Sweet K, Pilarski R, Pearlman R, Shane K, Brock P, Westman J, Chittenden A, Stopfer J, Schneider K, Sacca R, Stickevers S, Kipnis L, Koeller D, Gaonkar S, Sotelo J, Vaccari E, Cochrane S, Champine M, Espinel W, Lincoln SE, Nussbaum RL. Clinical utility of finding pathogenic mutations beyond BRCA1/2 in breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-03-01.

Systematic review: the use of nitrous oxide gas for lower gastrointestinal endoscopy

BACKGROUND

Nitrous oxide gas (N(2)O) has been proposed as an alternative to intravenous (i.v.) analgesia in patients undergoing lower gastrointestinal endoscopy.

AIM

To perform a systematic review of randomized studies where N(2)O was compared against control in patients undergoing either flexible sigmoidoscopy or colonoscopy.

METHODS

Electronic databases were searched; reference lists were checked and letters were sent to authors requesting data. Methodological quality was assessed. Data were tabulated on the duration and difficulty of the procedure, quality of sedation and speed of patient recovery.

RESULTS

A total of 11 studies were identified containing 623 patients. No differences were seen between groups for duration, difficulty of procedure or complications. Patient-reported pain was similar for N(2)O when undergoing flexible sigmoidoscopy vs. no sedation and when undergoing colonoscopy vs. i.v. sedation. Differences in delivery of N(2)O were identified. In all studies, N(2)O was associated with a more rapid recovery than i.v. sedation.

CONCLUSION

For patients undergoing colonoscopy, N(2)O provides comparable analgesia to i.v. sedation. The rapid psychomotor recovery with N(2)O enables quicker patient discharge and removes the need for a patient to be chaperoned. Benefit was not seen from N(2)O in patients undergoing flexible sigmoidoscopy possibly because it was delivered on demand rather than continuously.

Factors influencing the incidence and prevalence of food allergy

Food allergy is an increasing problem in Europe and elsewhere and severe reactions to food are also becoming more common. As food allergy is usually associated with other forms of allergic sensitisation it is likely that many risk factors are common to all forms of allergy. However the potential severity of the disease and the specific public heath measures required for food allergy make it important to identify the specific risk factors for this condition. Food allergy is unusual in that it often manifests itself very early in life and commonly remits with the development of tolerance. Hypotheses that explain the distribution of food allergy include specific genetic polymorphisms, the nature of the allergens involved and the unique exposure to large quantities of allergen through the gut. Progress has been made in developing more specific and testable hypotheses but the evidence for any of these is still only preliminary. Further collaborative research is required to develop an appropriate public health response to this growing problem.

Perceptions of facial aesthetics in two and three dimensions

The aims of this study were to investigate whether the preferred facial relationship chosen by professionals and the general public is Class I and to ascertain whether viewing two-dimensional (2D) or three-dimensional (3D) images had any effect on the ranking of facial attractiveness. Orthodontists (n = 47), maxillofacial surgeons (n = 25) and members of the general public (n = 78) assessed 2D and 3D facial scans of two males and two females that had been morphed to produce five images reflecting different skeletal patterns: Class I, mild and moderate Class II, and mild and moderate Class III. Each assessor placed the images in rank order of preference, after viewing alternate 2D and 3D image formats for each face. The data were analysed using logistic regression. In 2D, professionals (orthodontists and maxillofacial surgeons) chose Class I as the preferred facial image more frequently than the general public for only one of the four faces. However, in 3D format they chose Class I as the preferred facial image for some subject faces more, and others less, frequently when compared with the general public. The gender of the assessor was not significant when assessing the preferred facial relationship for Class I images in either 2D or 3D formats. The oldest assessors (56+ years) were significantly less likely than the younger age groups to select Class I as the preferred facial relationship in both 2D and 3D. In summary, there was too great a degree of variation to say that a difference between 2D and 3D facial images was evident.

Corticotropin-releasing factor 1 receptor-mediated mechanisms inhibit colonic hypersensitivity in rats

The potential relationship between stress and irritable bowel syndrome (IBS) symptomatology suggests a possible role for stress-mediating hormones, such as corticotropin-releasing factor (CRF), in the altered perception of stimuli in IBS patients. In previous studies, Wistar-Kyoto (WKY) rats with genetic indices of high anxiety demonstrated colonic hypersensitivity coupled with a high basal level of CRF within the central nervous system. In the current study we tested the hypothesis that a selective, non-peptide CRF1 receptor antagonist, antalarmin, would inhibit hypersensitivity in the WKY rat colon. Colonic sensitivity was determined by monitoring a visceromotor behavioural response during innocuous levels of colorectal distention (30 mmHg). In high anxiety WKY rats we found that antalarmin (20 mg kg-1, i.p.) significantly decreased the visceromotor response induced by colorectal distention. In a second study central administration (i.c.v.) of CRF was used to induce colonic hypersensitivity in lower anxiety Fischer 344 (F-344) rats, and in this model, antalarmin significantly inhibited the CRF-induced colonic hypersensitivity. In summary, a selective CRF1 receptor antagonist, antalarmin, inhibits colonic hypersensitivity apparent in WKY rats or in F-344 rats given a central administration of CRF. Our findings suggest that CRF1 receptor antagonism may represent a novel therapeutic approach for the treatment of IBS.

Coronary care nurses' clinical decision making

Increasing acuity of hospitalized persons with cardiac disease places great demands on nurses' decision-making abilities. Yet nursing lags in knowledge-based system development because of limited understanding about how nurses use knowledge to make decisions. The two research questions for this study were: how do the lines of reasoning used by experienced coronary care nurses compare with those used by new coronary care nurses in a representative sample of hypothetical patient cases, and are the predominant lines of reasoning used by coronary care nurses in hypothetical situations similar to those used for comparable situations in clinical practice? Line of reasoning was defined as a set of arguments in which knowledge is embedded within decision-making processes that lead to a conclusion. Sixteen subjects (eight experienced and eight new nurses) from coronary care and coronary step-down units in a large, private, teaching hospital in Minnesota, USA, were asked to think aloud while making clinical decisions about six hypothetical cases and comparable actual case. One finding was that most subjects in both groups used multiple lines of reasoning per case; but they used only one predominantly. This finding highlighted the non-linear nature of clinical decision making. Subjects used 25 predominant lines of reasoning, with intergroup differences on six of them. Where there were differences, experienced nurses used lines of reasoning of lower quality than did new subjects. The type variability in lines of reasoning suggested that multiple pathways should be incorporated into knowledge-system design. One implication of the variability in subjects' line of reasoning quality is that nurses at all levels of expertise are fallible and could benefit from decision support. The finding that subjects tended to use similar lines of reasoning for comparable hypothetical and actual cases was modest validation of subjects' performance on hypothetical cases as representing their decision making in practice. Consequently, there was support for using simulations and case studies in teaching and studying clinical decision making.

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.

Care of patients undergoing immunoglobulin therapy

Immunoglobulin infusion is becoming more widely used as treatment for a variety of conditions. This article describes the background and uses of immunoglobulin therapy and the nursing care of patients undergoing this treatment.

A previously undescribed mutation within the tetramerisation domain of TP53 in a family with Li-Fraumeni syndrome

We report details of a family with classic Li-Fraumeni syndrome in which there is a mutation in codon 344 of the tumour suppressor gene TP53. Codon 344 is a key residue within the tetramerisation domain, and the amino acid substitution of a proline for a leucine is predicted to have profound implications for tetramerisation and potentially DNA binding. This is the first report of a mutation at this residue in either sporadic tumours or in the germline and the first report of a germline mutation within the tetramerisation domain. The family does not appear to be remarkable in the spectrum of tumours, and there is loss of the wild-type allele in a leiomyosarcoma from the proband. A cell line has been established from the tumour of the proband and cytogenetic and molecular studies carried out, providing an extensive analysis in this family.

Consortium fine localization of X-linked Charcot-Marie-Tooth disease (CMTX1): additional support that connexin32 is the defect in CMTX1

Charcot-Marie-Tooth (CMT) disease is the most common form of inherited motor and sensory neuropathy. X-linked CMT (CMTX1) has been localized to the pericentric region of the X chromosome. Recently, mutations have been defined in the connexin32 gene that cosegregate with the CMTX1 phenotype in several families. The present paper presents the results of an international consortium to fine map the gene for CMTX1 to a small segment of Xq12-13. The linkage data, together with the molecular genetic studies, support the hypothesis that connexin32 is the genetic defect in CMTX1.

Surveillance of adverse reactions in patients self-infusing intravenous immunoglobulin at home

This is the first prospective study of adverse reactions occurring in primary-antibody-deficient patients self-infusing intravenous immunoglobulin at home. One hundred nineteen patients, already self-infusing at home, were entered into the study. They had been fully instructed about all aspects of adverse reactions, including their prevention and treatment. In the event of any adverse reaction, a form was completed detailing the product, the dose, the symptoms that occurred and the time they lasted, the rate of infusion, and other relative information such as predisposing factors and any medication taken. The severity of reactions were classified as mild, moderate, or severe. The total number of reactions documented was 19 in 2031 infusions, and all resolved without medical aid. No serious reactions occurred. Excluding those reactions in which predisposing factors were identified, the overall reaction rate was 0.7%. In conclusion the study showed the reaction rate in patients self-infusing intravenous immunoglobulin at home was low following formal training of selected patients at recognized training centers.

Pitfalls in the interpretation of spectral analysis of the heart rate variability during exercise in humans

The recent use of spectral analysis of the R-R interval variability to assess the autonomic drive during exercise has produced inconsistent results. The purpose of this study was to assess whether the spectral components of the R-R interval variability reflect different mechanisms at rest and during exercise. Autoregressive spectral analysis of the electrocardiographic and breathing signals was performed in 11 healthy young men at rest and during incremental cycle ergometry. The amplitude of respiratory sinus arrhythmia, i.e. the absolute power of the high frequency spectral component, fell at the onset of exercise, consistent with a reduction in cardiac vagal activity. Conversely, the normalized power of the high frequency component, (i.e. the percentage of R-R interval variance due to the respiratory sinus arrhythmia) increased with increasing work rates. The low frequency spectral component of the R-R interval variability, which when expressed in normalized units is believed to reflect cardiac sympathetic activity, was no longer detectable in severe exercise when the adrenergic drive is known to be elevated. In conclusion, autoregressive spectral analysis of the R-R interval variability does not adequately reflect the autonomic changes that occur during incremental exercise. In particular, the evidence indicates that as the cardiac vagal tone falls with increasing levels of exercise, a greater percentage of the residual power of the high frequency component may be due to non-neural mechanisms.

A mark of approval. Patient satisfaction with an i.v. self-infusion teaching programme

1. Self-infusion of IV immunoglobulin at home has many advantages for patients and their partners/carers. 2. To operate safely, home therapy programmes must include sufficient patient teaching and support. 3. Established home therapy patients were questioned on the service provided for them. 4. Overall, the service provided is perceived to be very good.

Serum soluble CD23 in patients with hypogammaglobulinaemia

Serum levels of the soluble form of the low-affinity receptor for IgE (FcERII, CD23) (sCD23) are elevated in autoimmune conditions associated with hypergammaglobulinaemia and B cell hyperactivity. Very high levels of sCD23 are found in patients with B-chronic lymphatic leukaemia (B-CLL) who are, however, frequently hypogammaglobulinaemic. We therefore compared the serum levels of sCD23 in healthy controls (n = 33) with three conditions associated with hypogammaglobulinaemia (HGG) and varying B cell numbers: X-linked agammaglobulinaemia (XLA, n = 12), common variable immunodeficiency (CVI, n = 20) and B-chronic lymphatic leukaemia (n = 33). Serum levels of sCD23 showed a significant correlation with the CD19+ B cell count in both normals and patients with CVI (r = 0.65, P < 0.0001). Amongst the different clinical groups, serum levels of sCD23 were increased in the order XLA < CVI < normals < CLL (medians 2.5, 7.7, 11.1 and 540, respectively; P < 0.001 for all comparisons except CVI versus normals P < 0.03 in a one-tailed test). In the CVI group, serum sCD23 was lowest amongst four patients with low B cell numbers. There was no overlap in sCD23 between patients with XLA and this subgroup of CVI patients. Serum sCD23 is, therefore, derived predominantly from B cells, and is significantly related to the peripheral blood B cell count.

Laryngeal paralysis-polyneuropathy complex in young Dalmatians

Clinical, morphologic, and morphometric findings are reported in 14 young Dalmatians with laryngeal paralysis. Neurologic signs, including megaesophagus, were observed in 13 of 14 dogs. Electromyographic abnormalities included fibrillation potentials and positive sharp waves in laryngeal, esophageal, facial, and distal appendicular muscles. Neurogenic atrophy was detected in intrinsic laryngeal and appendicular skeletal muscles. A diffuse, generalized polyneuropathy, dominated by axonal degeneration, was observed in recurrent laryngeal and appendicular peripheral nerves. Results of quantitative studies, using single teased fiber and cross-sectional nerve preparations, indicated that changes were more severe in distal parts of peripheral nerves, with preferential loss of medium sized (5.5 to 8 microns) and large-caliber (8.5 to 12 microns) myelinated nerve fibers. Ultrastructural alterations were observed in myelinated and unmyelinated nerve fibers. The term laryngeal paralysis-polyneuropathy complex is proposed for this apparent dying-back disorder, which is clinically, electrophysiologically, and pathologically different from laryngeal paralysis in young Bouvier des Flandres and Siberian Huskies. Prognosis for Dalmatians with laryngeal paralysis-polyneuropathy complex is guarded to poor. The condition is believed to be inherited.

X linked Charcot-Marie-Tooth disease (CMTX1): a study of 15 families with 12 highly informative polymorphisms

X linked dominant Charcot-Marie-Tooth disease (CMTX1) has previously been localised to Xq13-21. Fifteen families were studied using 12 highly informative polymorphisms in the pericentric region of the X chromosome. Phase known recombinations in these families localise the X linked dominant CMT gene to the region distal to DXS106 (Xq11.2-12) and proximal to DXS559 (Xq13.1). These markers flank approximately 2 to 3 Mb of DNA to which GJB1 and CCG1 have already been mapped. A recent report of mutations in the GJB1 gene in subjects with CMTX1 makes this a strong candidate gene.

Mutations in the connexin 32 gene in X-linked dominant Charcot-Marie-Tooth disease (CMTX1)

X-linked dominant Charcot-Marie-Tooth disease (CMTX1) is a peripheral neuropathy which maps to Xq13 and is flanked by the loci DXS106 (Xq11.2-q12) and DXS559 (Xq13.1). Contained within this interval of approximately 2-3Mb of DNA is the gene, connexin 32 (locus designation GJ beta 1). This gene encodes a gap junction protein which is expressed in large quantities within the liver and throughout a range of other mammalian tissues. We have sequenced the coding region of exon 2 of this gene from affected individuals in nine families with CMTX 1 and have found mutations which segregate with the disease in eight of these families. The mutations detected include missense point mutations at codons 15, 60, 63, 208, and 215, a nonsense point mutation at codon 220, deletions of one base in codon 72/3 producing a stop codon 12 codons down stream and a three base pair deletion which can be predicted to result in the loss of a single amino acid. These findings are consistent with the disease CMTX1 being the result of mutations affecting the gene connexin 32 (Cx32).

Knowing what to think by knowing who you are: self-categorization and the nature of norm formation, conformity and group polarization

We contrast two theoretical approaches to social influence, one stressing interpersonal dependence, conceptualized as normative and informational influence (Deutsch & Gerard, 1955), and the other stressing group membership, conceptualized as self-categorization and referent informational influence (Turner, Hogg, Oakes, Reicher & Wetherell, 1987). We argue that both social comparisons to reduce uncertainty and the existence of normative pressure to comply depend on perceiving the source of influence as belonging to one's own category. This study tested these two approaches using three influence paradigms. First we demonstrate that, in Sherif's (1936) autokinetic effect paradigm, the impact of confederates on the formation of a norm decreases as their membership of a different category is made more salient to subjects. Second, in the Asch (1956) conformity paradigm, surveillance effectively exerts normative pressure if done by an in-group but not by an out-group. In-group influence decreases and out-group influence increases when subjects respond privately. Self-report data indicate that in-group confederates create more subjective uncertainty than out-group confederates and public responding seems to increase cohesiveness with in-group - but decrease it with out-group - sources of influence. In our third experiment we use the group polarization paradigm (e.g. Burnstein & Vinokur, 1973) to demonstrate that, when categorical differences between two subgroups within a discussion group are made salient, convergence of opinion between the subgroups is inhibited. Taken together the experiments show that self-categorization can be a crucial determining factor in social influence.