Performance of BRCA1/2 mutation prediction models in male breast cancer patients.

To establish whether existing mutation prediction models can identify which male breast cancer (MBC) patients should be offered BRCA1 and BRCA2 diagnostic DNA screening, we compared the performance of BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm), BRCAPRO (BRCA probability) and the Myriad prevalence table ("Myriad"). These models were evaluated using the family data of 307 Dutch MBC probands tested for BRCA1/2, 58 (19%) of whom were carriers. We compared the numbers of observed vs predicted carriers and assessed the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) for each model. BOADICEA predicted the total number of BRCA1/2 mutation carriers quite accurately (observed/predicted ratio: 0.94). When a cut-off of 10% and 20% prior probability was used, BRCAPRO showed a non-significant better performance (observed/predicted ratio BOADICEA: 0.81, 95% confidence interval [CI]: [0.60-1.09] and 0.79, 95% CI: [0.57-1.09], vs. BRCAPRO: 1.02, 95% CI: [0.75-1.38] and 0.94, 95% CI: [0.68-1.31], respectively). Myriad underestimated the number of carriers in up to 69% of the cases. BRCAPRO showed a non-significant, higher AUC than BOADICEA (0.798 vs 0.776). Myriad showed a significantly lower AUC (0.671). BRCAPRO and BOADICEA can efficiently identify MBC patients as BRCA1/2 mutation carriers. Besides their general applicability, these tools will be of particular value in countries with limited healthcare resources.

Which screening strategy should be offered to women with BRCA1 or BRCA2 mutations? A simulation of comparative cost-effectiveness.

BACKGROUND: There is no consensus on the most effective strategy (mammography or magnetic resonance imaging (MRI)) for screening women with BRCA1 or BRCA2 mutations. The effectiveness and cost-effectiveness of the Dutch, UK and US screening strategies, which involve mammography and MRI at different ages and intervals were evaluated in high-risk women with BRCA1 or BRCA2 mutations. METHODS: Into a validated simulation screening model, outcomes and cost parameters were integrated from published and cancer registry data. Main outcomes were life-years gained and incremental cost-effectiveness ratios. The simulation was situated in the Netherlands as well as in the United Kingdom, comparing the Dutch, UK and US strategies with the population screening as a reference. A discount rate of 3% was applied to both costs and health benefits. RESULTS: In terms of life-years gained, the strategies from least to most cost-effective were the UK, Dutch and US screening strategy, respectively. However, the differences were small. Applying the US strategy in the Netherlands, the costs were €43 800 and 68 800 for an additional life-year gained for BRCA1 and BRCA2, respectively. At a threshold of €20 000 per life-year gained, implementing the US strategy in the Netherlands has a very low probability of being cost-effective. Stepping back to the less-effective UK strategy would save relatively little in costs and results in life-years lost. When implementing the screening strategies in the United Kingdom, the Dutch, as well as the US screening strategy have a high probability of being cost-effective. CONCLUSION: From a cost-effectiveness perspective, the Dutch screening strategy is preferred for screening high-risk women in the Netherlands as well as in the United Kingdom.

Rapid detection of BRCA1 mutations by the protein truncation test.

More than 75% of the reported mutations in the hereditary breast and ovarian cancer gene, BRCA1, result in truncated proteins. We have used the protein truncation test (PTT) to screen for mutations in exon 11, which encodes 61% of BRCA1. In 45 patients from breast and/or ovarian cancer families we found six novel mutations: two single nucleotide insertions, three small deletions (1-5 bp) and a nonsense mutation identified two unrelated families. Furthermore, we were able to amplify the remaining coding region by RT-PCR using lymphocyte RNA. Combined with PTT, we detected aberrantly spliced products affecting exons 5 and 6 in one of two BRCA1-linked families examined. The protein truncation test promises to become a valuable technique in detecting BRCA1 mutations.

Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study.

BACKGROUND: The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity. METHODS: To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively. RESULTS: There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10-2.04 and HR 2.16, 95%CI 1.24-3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele. CONCLUSION: The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers.

The introduction of a choice to learn pre-symptomatic DNA test results for BRCA or Lynch syndrome either face-to-face or by letter.

In predictive DNA testing for hereditary cancer, test results should traditionally be disclosed face-to-face. Increasingly, however, counselees ask to receive their test result at home by letter. To compare the quality of genetic counselling in the traditional way to a procedure in which counselees are offered a choice on how to get their test result. Counselees from families with a known BRCA1/2 or Lynch syndrome mutation were randomised into two groups. The control group was given the DNA test result in a face-to-face consultation. In the intervention group people could choose to learn their test result face-to-face or by letter. The quality of genetic counselling was assessed through questionnaires at three different moments. Data of 198 counselees were analysed. The quality of genetic counselling and psychological functioning were equally good in both groups. The majority of cases chose for disclosure by letter. The counselees with a good test result in the intervention group were the most satisfied. Our results indicate that in predictive DNA testing for BRCA1/2 and Lynch syndrome, a choice protocol is equally safe and more satisfying. Moreover, it is more efficient for both counsellor and counselee.

Perceiving cancer-risks and heredity-likelihood in genetic-counseling: how counselees recall and interpret BRCA 1/2-test results.

Previous studies on the counsellees' perception of DNA test results did not clarify whether counsellees were asked about their recollections or interpretations, and focused only on patients' own risks and not on the likelihood that cancer is heritable in the family. We tested differences and correlations of four perception aspects: recollections and interpretations of both cancer risks and heredity likelihood. In a retrospective study, women tested for BRCA1/2 on average, 5 years ago, completed questionnaires about their perception. Participants had received an unclassified variant (n = 76), uninformative (n = 76) or pathogenic mutation (n = 51) result in BRCA1/2. Analyses included t-tests, correlations and structural equation modelling. The counsellees' perception showed to consist of four distinctive phenomena: recollections and interpretations of cancer risks and of heredity likelihood. This distinctiveness was suggested by significant differences between these perception variables. Moderate to strong correlations were found between these variables, suggesting that these differences between variables were consistent. The relationships between these variables were not influenced by actually communicated DNA test results, sociodemographics, medical and pedigree information, or framing of cancer risk questions. The largest differences between recollections and interpretations were found in the unclassified variant group and the smallest in uninformatives. Cancer risks and heredity likelihood correlated least in the pathogenic mutation group. Communication of ambiguous genetic information enlarged the differences. To understand the counsellees' perception of genetic counselling, researchers should study recollections and interpretations of cancer risks and heredity likelihood. Genetic counsellors should explicitly address the counsellees' recollections and interpretations, and be aware of possible inaccuracies.

Genetic counseling of patients with ovarian carcinoma: acceptance, timing, and psychological wellbeing.

The new Dutch guidelines on hereditary and familial ovarian carcinoma recommend genetic testing of all patients with epithelial ovarian cancer (EOC). With this study, we aimed to obtain insight into (1) the acceptance and timing of the offer of genetic counseling in women with EOC, (2) reasons for accepting or declining genetic counseling, and (3) psychological differences between women who did and did not have genetic counseling. A multicenter questionnaire survey was performed in patients with EOC in four Dutch oncology centers. The questionnaire addressed whether, how, and when genetic counseling was offered, women's arguments to accept or decline genetic counseling, and included the Cancer Worry Scale (CWS) and the Hospital Anxiety and Depression Scale (HADS). A total of 67 women completed the questionnaire, of which 43 had genetic counseling. Despite a wide variability in the timing of the offer of genetic counseling, 89% of the women were satisfied with the timing. No significant differences were found between the CWS and HADS scores for the timing of the offer of genetic counseling and whether or not women had genetic counseling. Taking the small sample size into account, the results tentatively suggest that genetic counseling may have limited impact on the psychosocial wellbeing of women with EOC. Therefore, we assume that implementation of the new guidelines offering genetic counseling to all patients with EOC will not cause considerable additional burden to these patients.

Hospital transfer after a breast cancer diagnosis: A population-based study in the Netherlands of the extent, predictive characteristics and its impact on time to treatment.

PURPOSE: Patients may transfer of hospital for clinical reasons but this may delay time to treatment. The purpose of this study is to provide insight in the extent of hospital transfer in breast cancer care; which type of patients transfer and what is the impact on time to treatment. METHODS: We included 41,413 breast cancer patients registered in the Netherlands Cancer Registry between 2014 and 2016. We investigated transfer of hospital between diagnosis and first treatment being surgery or neoadjuvant chemotherapy (NAC). Co-variate adjusted characteristics predictive for hospital transfer were determined. To adjust for possible treatment by indication bias we used propensity score matching (PSM). Time to treatment in patients with and without hospital transfer was compared. RESULTS: Among 41,413 patients, 8.5% of all patients transferred to another hospital between diagnosis and first treatment; 4.9% before primary surgery and 24.8% before NAC. Especially young (aged <40 years) patients and those who underwent a mastectomy with immediate breast reconstruction (IBR) were more likely to transfer. The association of mastectomy with IBR with hospital transfer remained when using PSM. Hospital transfer after diagnosis significantly prolonged time to treatment; breast-conserving surgery by 5 days, mastectomy by 7 days, mastectomy with IBR by 9 days and NAC by 1 day. CONCLUSIONS: While almost 5% of Dutch patients treated with primary surgery transfer hospital after diagnosis and up to 25% for patients treated with NAC, our findings suggest that especially those treated with primary surgery are at risk for additional treatment delay by hospital transfer.

Georg Schmorl on trophoblasts in the maternal circulation.

Trafficking of cells between the fetus and its mother provides indirect clues to the underlying pathophysiology of pregnancy. Georg Schmorl first documented the presence of fetal cells in the maternal body and emphasized the importance of the placenta in eclampsia. Although his classic paper, written in 1893, is widely cited today, few investigators have actually read the paper, as it was published in German [Schmorl G., Pathologisch-anatomische Untersuchungen über Puerperal-Eklampsie. Verlag FCW Vogel, Leipzig; 1893]. Our goal was to translate the paper into English and critically re-evaluate its conclusions from a 21st century perspective. Schmorl was remarkably astute in his assessment of the pathologic changes that were seen in the 17 women on whom he performed complete autopsies. He found similar severe changes in all of the women, implying a common pathogenesis. This was in direct contrast to the then current doctrine. He was the first to observe the presence of thrombi containing multinucleated syncytial giant cells in the lungs of the women and speculated that they were of placental origin. To support his hypothesis he performed animal experiments. He also recognized that feto-maternal trafficking occurred in normal gestations but was increased in pregnancies affected by eclampsia. Using sophisticated molecular techniques we can now precisely confirm what Schmorl so elegantly described.

Psychological factors associated with the intention to choose for risk-reducing mastectomy in family cancer clinic attendees.

OBJECTIVES: Women seeking counseling because of familial breast cancer occurrence face difficult decisions, such as whether and when to opt for risk-reducing mastectomy (RRM) in case of BRCA1/2 mutation. Only limited research has been done to identify the psychological factors associated with the decision for RRM. This study investigated which psychological factors are related to the intention to choose for RRM. MATERIALS & METHODS: A cohort of 486 cancer-unaffected women with a family history of breast cancer completed the following questionnaires prior to genetic counseling: the Cancer Worry Scale, Positive And Negative Affect Scale, Perceived Personal Control Scale, Hospital Anxiety and Depression Scale and State Anxiety Scale and questions regarding socio-demographic characteristics, family history, risk perception and RRM intention. Multivariate logistic regression was used to analyze the relation between psychological factors and women's intention to choose for RRM. RESULTS: Factors associated with RRM intention were high positive affect (OR = 1.86, 95%CI = 1.12-3.08), high negative affect (OR = 2.52, 95%CI = 1.44-4.43), high cancer worry (OR = 1.65, 95%CI = 1.00-2.72), high perceived personal control (OR = 3.58, 95%CI = 2.18-5.89), high risk-perception (OR = 1.85, 95%CI = 1.15-2.95) and having children (OR = 2.06, 95%CI = 1.21-3.50). CONCLUSION: Negative and positive affects play an important role in the intention for RRM. Furthermore, perceived personal control over the situation is associated with an intention for RRM. In addition to focusing on accurate risk communication, counseling should pay attention to the influence of perceived control and emotions to facilitate decision-making.

Randomized trial of a shared decision-making intervention consisting of trade-offs and individualized treatment information for BRCA1/2 mutation carriers.

PURPOSE: To evaluate a shared decision-making intervention (SDMI) for BRCA1/2 mutation carriers who have to make a choice between screening and prophylactic surgery for breasts and/or ovaries. PATIENTS AND METHODS: The SDMI consisted of two value assessment sessions, using the time trade-off method, followed by individualized treatment information based on (quality-adjusted) life expectancy. After the baseline assessment (2 weeks after a positive DNA test result), women were randomly assigned to the SDMI group (n = 44), receiving the SDMI 2 months after the test result, or to the control group (n = 44). The short- and long-term effects, 3 and 9 months after the test result, were assessed using questionnaires. Data were collected on well-being, treatment choice, and decision-related outcomes. RESULTS: In the short term, the SDMI had no effect. In the long term, with respect to well-being, patients in the SDMI group had less intrusive thoughts (P =.05) and better general health (P =.01) and tended to be less depressed (P =.07). With respect to decision-related outcomes for the breasts, the SDMI group held stronger preferences (P =.02) and agreed more strongly to having weighed the pros and cons (P =.01). No effect was found on treatment choice. In the long term, interaction effects between the SDMI and cancer history were found. The SDMI showed an overall beneficial effect for unaffected women, whereas affected women tended to experience detrimental effects. CONCLUSION: We conclude that the SDMI improved decision making in unaffected BRCA1/2 mutation carriers. Supporting decision making in a systematic way using trade-offs is beneficial for these women.

Genes other than BRCA1 and BRCA2 involved in breast cancer susceptibility.

This review focuses on genes other than the high penetrance genes BRCA1 and BRCA2 that are involved in breast cancer susceptibility. The goal of this review is the discovery of polymorphisms that are either associated with breast cancer or that are in strong linkage disequilibrium with breast cancer causing variants. An association with breast cancer at a 5% significance level was found for 13 polymorphisms in 10 genes described in more than one breast cancer study. Our data will help focus on the further analysis of genetic polymorphisms in populations of appropriate size, and especially on the combinations of such polymorphisms. This will facilitate determination of population attributable risks, understanding of gene-gene interactions, and improving estimates of genetic cancer risks.

Accuracy of family history of cancer: clinical genetic implications.

Family medical history is the cornerstone of clinical genetic diagnosis and management in cases of familial cancer. The soundness of medical decisions can be compromised if reports by the family on affected relatives are inaccurate. Although very time consuming, family medical histories are therefore routinely verified. To investigate whether such verification is clinically justified, we retrospectively analysed the accuracy of a consecutive series of 383 tumour reports from counsellees on 120 families in our clinic. We evaluated these families for the impact of verification on clinical genetic diagnosis and management. Accuracy according to cancer type showed marked variation, ranging from 93% and 89% for breast cancer and colorectal cancer, respectively, to 42% and 37% for extra-colorectal alimentary tract cancer and uterine cancer. Accuracy was related to the degree of kinship of the affected relative, but not to age and gender of the counsellee, nor to the reason for referral or personal history of cancer. Age at diagnosis and multiple primary tumours were reported accurately in 97% and 94% of cases, respectively. In six out of 120 families verification data changed clinical genetic management, in five of these the genetic risk was reduced. Although verification of all reported cancer cases in a family remains the 'gold standard' for clinical as well as research purposes, verification of reports on breast cancer can be limited without seriously compromising medical decision making. In cases where verification is impossible because medical records are unavailable, findings from studies such as ours may help in interpreting family histories.

An Xp22.1-p22.2 YAC contig encompassing the disease loci for RS, KFSD, CLS, HYP and RP15: refined localization of RS.

To facilitate the positional cloning of the genes involved in retinoschisis (RS), keratosis follicularis spinulosa decalvans (KFSD), Coffin-Lowry syndrome (CLS), X-linked hypophosphatemic rickets (XLH, locus name HYP) and X-linked dominant cone-rod degeneration (locus name RP15), we have extended the molecular map of the Xp22 region. Screening of several YAC libraries allowed us to identify 156 YACs, 52 of which localize between markers DXS414 (P90) and DXS451 (kQST80H1). Analysis of their marker content facilitated the construction of a YAC contig from the region spanning (in this order): DXS414 - DXS987 - DXS207 - DXS1053 - DXS197 - DXS 43 - DXS1195 - DXS418 - DXS999 - PDHA1 - DXS7161 - DXS443 - DXS 7592 - DXS1229 - DXS365 - DXS7101 - DXS7593 - DXS1052 - DXS274 - DXS989 - DXS451. The region between DXS414 and DXS451 covers about 4.5-5 Mb. Two additional markers (DXS7593 and DXS7592) were placed in the region, thereby increasing the genetic resolution. Using the deduced marker order, the analysis of key recombinants in families segregating RS allowed us to refine the critical region for RS to 0.6 Mb, between DXS418 and DXS7161.

Cardiac involvement in carriers of Duchenne and Becker muscular dystrophy.

A cross-sectional study in a cohort of DNA proven carriers of Duchenne (DMD) and Becker (BMD) muscular dystrophy was undertaken with the following objectives: (1) to estimate the frequency of electrocardiographic (ECG) and echocardiographic abnormalities; (2) to establish the proportion of carriers with dilated cardiomyopathy and (3) to assess possible associations between dilated cardiomyopathy and genotype. One hundred and twenty nine DMD and BMD carriers, aged 18-60 years, were traced through the files of the central register kept at the department of Human Genetics in Leiden. Investigations included full medical history, physical examination, ECG and two-dimensional and M-mode echocardiographic examination. Forty-seven percent had ECG changes. Thirty-six percent (DMD 41%, BMD 27%) had at least one abnormality as is usually found in the male patients. Echocardiographic examination was abnormal in 36% (DMD 38%, BMD 34%). Dilated cardiomyopathy was found in seven DMD carriers (8%), and in none of BMD carriers. In addition, 18% had left ventricle dilatation (DMD 19%, BMD 16%). Only 38% had a completely normal investigation of the heart. We found no association between genotype and cardiac manifestations. Our study underlines that cardiac involvement is part of the dystrophinopathies. Carriers should be told about the increased risk of this complication when asking genetic advice. It also implicates that a complete cardiological evaluation should be performed at least once in all carriers. If left ventricle dilatation or dilated cardiomyopathy is present a yearly follow up is needed, in order to start timely therapy.

Body wall defects in two sibs.

We describe 2 sibs, a male fetus with an unusual lumbar hernia and spina bifida occulta, and a female fetus with a median abdominoschisis. The first fetus had some signs of lumbocostovertebral syndrome (LCVS), which consists of a congenital lumbar hernia and associated abnormalities such as absent or hypoplastic ribs, hemivertebrae, and scoliosis. Abdominoschisis has not been described in LCVS, and the given abnormalities in the 2 sibs have not been published to date. One can hypothesize that vascular disruption of a somite or a group of somites may result in the described abdominal wall defects. We conclude that these abnormalities could be coincidental in the 2 sibs or could have a related, probably multifactorial, cause.

Cartilage hair hypoplasia, metaphyseal chondrodysplasia type McKusick: description of seven patients and review of the literature.

We describe 7 cases of cartilage hair hypoplasia (CHH) with emphasis on the clinical and immunological aspects. The literature on CHH is reviewed and symptoms in 63 non-Amish cases are summarized. In this autosomal recessive disorder the immunodeficiency, hair abnormalities, and severity of skeletal involvement show extremely variable expressivity, between and within families. Two of the 3 sib-pairs among our cases demonstrate the great difference in expression within one family. At adult age roentgenological abnormalities can be very mild, or even absent. An impairment in cell-mediated immunity is present in all of our cases and seems a consistent manifestation in CHH; however, sometimes it is very subtle and without clinical symptoms.

BRCA1 in the family: a case description of the psychological implications.

Our experience with the first family in the Netherlands for whom predictive DNA-testing for Hereditary Breast and Ovarian Cancer (HBOC) became an option is described. This serves to illustrate the complex emotional impact on a family as a whole, and upon the members separately, of becoming aware that breast and ovarian cancer is hereditary, and the implications of undergoing predictive testing. All family members received genetic counseling and were offered pre- and post-test psychological follow-up. We observed two important roles within the family. One member became "the messenger of the news" informing the relatives of the hereditary character of cancer in the family. Another was "the first utilizer" of the new options; namely, the predictive DNA-test and preventive surgery. This first utilizer became the example to the rest of the family. Decisions made about preventive treatment (prophylactic ovariectomy and/or mastectomy) were based on the experiences within the family, whether one identified with an affected family member with breast or with ovarian cancer. The actions and reactions perceived were illustrative of what kind of support provisions should be provided in addition to the genetic and oncological counseling for HBOC. Moreover HBOC should be considered both as an individual and a family problem and be treated as such in genetic counseling.

MRI screening for breast cancer in women with familial or genetic predisposition: design of the Dutch National Study (MRISC).

Mammography screening of women aged 50-70 years for breast cancer has proven to be effective in reducing breast cancer mortality. There is no consensus about the value of breast cancer screening in women aged 40-49 years. Five to ten per cent of all breast cancers are hereditary. One of the options to reduce the risk of breast cancer mortality for women with a familial or genetic predisposition is intensive surveillance. However, the effectiveness of mammography screening for breast cancer in these women, who are mainly younger than 50 years, is unproven. MRI might increase the effectiveness of screening in women with a familial or genetic predisposition. This paper describes the design of the Dutch national study for Magnetic Resonance Imaging (MRI) screening in women with a familial or genetic predisposition. The aims of this study are to investigate: the value of regular surveillance in women with a familial or genetic predisposition for breast cancer, the efficacy of MRI as compared to mammography, cost-effectiveness of regular screening and quality of life during surveillance. Included are women with a lifetime risk of familial breast cancer of 15% or more or BRCA1/2 mutation carriers, who visit one of the Dutch family cancer clinics. The aim is to include 2,500 women. The study started on 1 November 1999. On 1 January 2002, more than 1,700 women, including 210 proven carriers of a BRCA1 or BRCA2 mutation, were included in the study.

Determination of a maximum number of artificial inseminations by donor children per sperm donor.

OBJECTIVE: To determine a safe maximum number of artificial insemination (donor insemination [DI]) children per anonymous sperm donor. DESIGN: Multiparameter calculation model of contribution of DI to inbreeding. SETTING: Data of the collaborative DI centers and demographic population data of The Netherlands. INTERVENTIONS: Calculations of the contribution of DI to inbreeding were made, taking into account all possible unintentional consanguineous matings and consanguineous inseminations with a coefficient of inbreeding (F) of > or = 1/16 for the offspring. MAIN OUTCOME MEASURE: Coefficient of inbreeding (F). RESULTS: The contribution of DI to inbreeding was estimated to be 46.6 x 10(-6) + k (1.66 x 10(-6)) (k = number of DI children per donor). When only half-sibling matings were considered, the kmax was 32. When all possible consanguineous matings and inseminations were taken into account, kmax decreased with 28% to 25 children. CONCLUSION: Calculations of a maximum number of DI children per sperm donor, based on possible enhancement of inbreeding and given the Dutch population and DI setting, show that 25 children per DI donor is a safe threshold for clinical practice.