The effect of orthodontic treatment on smile attractiveness: a systematic review

BACKGROUND

Smile attractiveness is a primary factor for patients to seek orthodontic treatment, however, there is yet no systematic evaluation of this topic in the literature.

OBJECTIVES

To assess the current evidence on the effect of orthodontic treatment on smile attractiveness.

SEARCH METHODS

Seven electronic databases (MEDLINE, Cochrane Library, Virtual Health Library, SCOPUS, Web of Science, Google Scholar and Embase) were searched on 14 September 2022.

SELECTION CRITERIA

Studies evaluating smile attractiveness before and after orthodontic treatment or only after completion of orthodontic treatment.

DATA COLLECTION AND ANALYSIS

Extracted data included study design and setting, sample size and demographics, malocclusion type, treatment modality and method for outcome assessment. Risk of bias was assessed with the ROBINS-I tool for non-randomised studies. Random-effects meta-analyses of mean differences and their 95% confidence intervals (CIs) were planned a priori.

METHODS

After elimination of duplicate studies, data extraction and risk of bias assessment according to the Cochrane guidelines, an evaluation of the overall evidence was performed. The included studies were evaluated based on the characteristics of their study and control groups and based on their main research question. Also, all outcome measures were standardized into a common assessment scale (0-100), in order to obtain more easily interpretable results.

RESULTS

Ten studies were included in this review, nine of which were assessed as being at serious risk of bias and one at moderate risk of bias. The large heterogeneity between the included studies did not allow for a meta-analysis. Orthodontic treatment has a moderately positive effect on smile attractiveness. When compared to no treatment, orthodontic treatment with premolar extractions improves smile attractiveness by 22%. Also, surgical correction of Class III cases increases smile attractiveness by 7.5% more than camouflage treatment. No other significant differences were shown between different types of treatment.

CONCLUSION

Based on the available data, orthodontic treatment seems to moderately improve the attractiveness of the smile. There is significant bias in the current literature assessing the effect of orthodontics on smile attractiveness; therefore, the results cannot be accepted with certainty.

Early Optimistic Effect in Periodontology and Implant Dentistry Trials

Differences in effect estimates between early primary trials included in a meta-analysis and the pooled estimate of meta-analysis might indicate potential novelty bias. The objective of this study was to assess the presence of novelty bias in a sample of studies published in periodontology and implant dentistry. On August 7, 2020, we searched the PubMed database for meta-analyses of clinical studies published between August 2015 and August 2020. Meta-analyses with at least 4 primary studies were selected for assessment. We fitted logistic regression models using trial characteristics as predictors to assess the association between these characteristics and 1) the odds of the first trial's estimate to be included in the meta-analysis confidence interval (CI) and 2) the odds of overlap between the first trial's CI and the meta-analysis prediction interval (PI). Ninety-two meta-analyses provided data for assessment. In absolute values, 70% of the meta-analyses have a pooled estimate smaller than the corresponding estimate of the first trial, although there was overlap of the CI of estimates from the first trial and the meta-analysis in 87% of the cases. This is probably due to the small number of trials in most meta-analyses and the subsequently large uncertainty associated with the pooled effect estimate. As the number of trials in the meta-analysis increased, the odds of the treatment effect estimate of the first trial to be included in the meta-analysis CI decreased by 15% for every additional trial (odds ratio, 0.85; 95% CI, 0.73 to 0.96). Meta-analytic effect estimates appear to be more conservative than those from the first trial in the meta-analysis. Our findings show evidence of novelty bias in periodontology and implant dentistry; therefore, clinicians should be aware of the risk of making decisions based on the information reported in new trials because of the risk of exaggerated estimates in these trials.

Dental Research Waste in Design, Analysis, and Reporting: A Scoping Review

Research waste is highly prevalent across biomedical investigations. We aimed to assess the evidence on the extent of research waste in dental research. We performed a scoping review of empirical evaluations of dental studies assessing the prevalence and impact of limitations in design, conduct, analysis, and reporting of research. PubMed was searched using specific terms to retrieve studies dealing with design, conduct, analysis, and reporting of studies in dentistry, with no year or language restrictions. Of the 1,807 publications identified from the search and from manual searches, 71 were included in this review. The topic and article selection was based on the expert opinion of the authors. The existing evidence suggests that, although there are improvements over time, substantial deficiencies in all areas (design, conduct, analysis, reporting) were prevalent in dental research publications. Waste in research is a multifaceted problem without a simple solution. However, an appreciation of optimal research design and execution is a prerequisite and should be underpinned by policies that include appropriate training in research methods and properly aligned incentives.

Quantitative evaluation of the progressive wear of powered interproximal reduction systems after repeated use : An in vitro study

PURPOSE

To evaluate the residual surface roughness of 5 common diamond-coated interproximal reduction (IPR) systems after consecutive in vitro applications in relation to system, diamond grain size, and instrument thickness.

METHODS

IPR was performed on 80 extracted human incisors using motor-driven strips and discs under predefined conditions. The IPR auxiliaries were applied at 5 consecutive sessions of 20 s on intact interproximal surfaces, and the surface profile (R_a, R_z, R_max) was analyzed at baseline and after each session with an optical profilometer.

RESULTS

No overall significant difference in the roughness values was found between systems (P = 0.07 for R_a, P = 0.33 for R_z, and P = 0.48 for R_max). There was a significant average decrease of R_a, R_z, and R_max for all systems for every unit increase in time by -0.171 μm (P < 0.001), -3.297 (P ≤ 0.001), and -2.788 μm (P = 0.001), respectively. R_a, R_z, and R_max values increased significantly, i.e., by 0.194 μm (P = 0.003), 5.890 μm (P = 0.001), and 5.319 μm (P = 0.010) as instrument thickness increased by one unit. No significant reductions in R_a, R_z, and R_max were observed across grain sizes (-0.008 μm [P > 0.05], -0.244 μm [P > 0.05], and -0.179 μm [P > 0.05], respectively). There was no evidence of interaction between system and time as the P values for R_a, R_z, and R_max were 0.88, 0.51, and 0.70, respectively.

CONCLUSIONS

All IPR materials presented significant gradual decrease of surface roughness after repeated applications. There were no significant roughness changes among auxiliaries of different grain sizes. Thinner auxiliaries showed significantly more roughness reduction, possibly requiring more frequent replacement than thick auxiliaries in clinical practice.

Quality assessment of clinical practice guidelines used in oral and maxillofacial surgery

An assessment of the quality of oral and maxillofacial surgery clinical practice guidelines is lacking. The aim of this investigation was to assess the quality of guidelines using the RIGHT (Reporting Items for practice Guidelines in HealThcare) checklist. The primary outcome was to assess the score (quality) of guidelines based on the RIGHT checklist and to identify predictors (region, type, single or multi-centre, and speciality/non-speciality) influencing the quality score. In this review, following a search of electronic databases and national society websites, a total of 25 guidelines were independently assessed by two assessors against the 22-item RIGHT checklist. Inter-assessor reliability was assessed. Deficiencies in the reporting of items relating to limitations, funding, declaration and management of interests, healthcare questions, and quality assurance were evident. The median overall score for the guidelines was 28 (range 14-66). Guidelines produced by multiple centres (β=57.15, 95% confidence interval -26.62 to 87.68, P= 0.001, multivariate analysis) and non-speciality societies (β=20, 95% confidence interval -0.03 to 40.03, P=0.05, univariate analysis) tended to have higher quality scores. Overall, the quality of clinical practice guidelines used in oral and maxillofacial surgery was deemed suboptimal. If clinical practice guidelines are to be used in making treatment decisions for patients, clinicians should be aware of their possible limitations.

Information for oral and maxillofacial patients: can it be improved?

The aim and objective of this study was to evaluate the quality and readability of leaflet and online Oral and Maxillofacial Surgery patient information leaflets (PILs). The quality, readability and grade level of each PIL was assessed using the DISCERN, Flesch Reading Ease and Flesh-Kincaid Grade Level instruments respectively. In total, 140 patient information leaflets were assessed. For both leaflet and online PILs, many items of the DISCERN instrument were deemed of low quality and poorly reported. The median overall quality score was 30.2. Variation in the quality and readability scores between leaflet and online PILs and those produced by various societies was evident. Overall, PILs were deemed to be of moderate quality. Online PILs were of lower quality, more difficult to read and aimed at a higher reading age level.

CONSORT 2010 statement: extension checklist for reporting within person randomised trials

Evidence shows that the quality of reporting of randomised controlled trials (RCTs) is not optimal. The lack of transparent reporting impedes readers from judging the reliability and validity of trial findings and researchers from extracting information for systematic reviews and results in research waste. The Consolidated Standards of Reporting Trials (CONSORT) statement was developed to improve the reporting of RCTs. Within person trials are used for conditions that can affect two or more body sites, and are a useful and efficient tool because the comparisons between interventions are within people. Such trials are most commonly conducted in ophthalmology, dentistry, and dermatology. The reporting of within person trials has, however, been variable and incomplete, hindering their use in clinical decision making and by future researchers. This document presents the CONSORT extension to within person trials. It aims to facilitate the reporting of these trials. It extends 16 items of the CONSORT 2010 checklist and introduces a modified flowchart and baseline table to enhance transparency. Examples of good reporting and evidence based rationale for CONSORT within person checklist items are provided.

Collaboration in orthodontic clinical trials: prevalence and association with sample size and funding

BACKGROUND

To assess patterns of research collaboration in orthodontics and possible relationships with sample size and funding status.

METHODS

Orthodontic randomised and non-randomised controlled clinical trials published between 2013 and 2017 were identified through electronic searching. The nature of collaboration, author institutions, study setting, sample size, and funding status were assessed. Linear and logistic regression analyses were applied.

RESULTS

Of 1153 studies, 217 met the selection criteria. The majority of studies were authored by university academics (86%), were conducted in a single centre (71.9%) and in at least one university hospital (68.2%). The number of practice-based trials (10.1%), as well as the involvement of specialist practitioners (5.2%) in co-authorship, was limited. Multi-centred studies within a single country were associated with a significantly larger sample size compared to single-centred trials (P = 0.00; 95% confidence interval [CI] 33.59, 106.93). However, authorship collaboration either nationally (odds ratio [OR] 2.37; 95% CI 0.85, 6.57) or internationally across different continents (OR 5.54; 95% CI 0.62, 49.52) did not translate into increased funding.

CONCLUSIONS

Most orthodontic studies were undertaken in university hospital settings within a single country. Collaboration is common in orthodontics but involvement of practice settings remains limited, suggesting a need for stimulation of practice-based research and research partnerships.

A cross-sectional analysis of Wits and Riedel in adults with skeletal III malocclusion: How informative are they?

OBJECTIVES

To compare the relationship between Riedel and Wits appraisal in skeletal III malocclusions and to assess the effect of variation in the vertical skeletal measurements.

SETTING AND SAMPLE POPULATION

One-hundred and twenty consecutive subjects with Class III malocclusions attending orthognathic clinics were analysed.

MATERIALS AND METHODS

Lateral cephalograms were hand-traced under standardized conditions. Cephalometric measurements included Riedel analysis, Wits appraisal, A point/B point to Frankfurt plane (AF-BF) and vertical measurements.

RESULTS

The mean ANB and Wits values were -3.22° and -11.39 mm, respectively. A positive correlation was found between ANB and Wits overall (r = -.49; P < .001). However, there was poor agreement between both Wits (r = .087) and Riedel (r = .089) with AF-BF (P > .05). A negative correlation existed between Wits and LAFH% (r = -.64, P-value < .001); however, no relationship was observed between ANB and LAFH% (P > .05) based on linear regression analysis.

CONCLUSIONS

There is a positive relationship between ANB and Wits; however, neither correlated well with a purer antero-posterior assessment (AF-BF). Furthermore, variations in the vertical skeletal measurements affect the strength of agreement. Caution is advised in the interpretation of antero-posterior analysis especially in the presence of vertical discrepancy.

A prospective cohort study assessing the appearance of retrieved aesthetic orthodontic archwires

OBJECTIVES

To investigate the appearance of three esthetic nickel titanium (NiTi) wires after 6 weeks of intra-oral cycling and to determine the association between objective and subjective measures of esthetics.

SETTING AND SAMPLE POPULATION

A prospective cohort study was undertaken involving participants undergoing upper fixed orthodontic appliance treatment with ceramic brackets.

MATERIALS AND METHODS

Fifty participants were assigned to one of three groups of NiTi esthetic wires (American Orthodontics Ever White™, Forestadent Biocosmetic™ and GAC High Aesthetic™), with wires retrieved after 6 weeks in situ. Participants completed a bespoke questionnaire exploring perceptions of wire esthetics. Objective measurement of coating loss was undertaken using a custom arch wire jig.

RESULTS

American Orthodontics Ever White™ had the greatest mean coating loss (50.7%) followed by Forestadent Biocosmetic™ (6%), with GAC High Aesthetic TM undergoing minimal loss (0.07%) (P < .001). The majority of coating loss with the American Orthodontics Ever White™ wires arose in the anterior region while Forestadent Biocosmetic™ wires and GAC High Aesthetic™ wires exhibited coating loss posteriorly (P < .001). These findings were reflected in the subjective assessment with a negative correlation found between coating loss and final Visual Analogue Scale scores (P < .001).

CONCLUSIONS

Considerable esthetic variation between arch wires following 6 weeks of intraoral cycling was identified in this prospective cohort study. Intraoral cycling has a negative impact on participant perception of arch wire esthetics, and objective and subjective assessment of wire esthetics appears to be consistent.

Statins in nonsurgical and surgical periodontal therapy. A systematic review and meta-analysis of preclinical in vivo trials

The cholesterol-lowering drugs, statins, possess anti-inflammatory, antimicrobial and pro-osteogenic properties, and thus have been tested as an adjunct to periodontal treatment. The present systematic review aimed to answer the following focused research question: What is the effect of local and/or systemic statin use on periodontal tissues in preclinical in vivo studies of experimentally induced periodontitis (EIP) and/or acute/chronified periodontal defect (ACP) models? A literature search (of Medline/PubMed, Embase/Ovid, CENTRAL/Ovid) using the following main eligibility criteria was performed: (i) English or German language; (ii) controlled preclinical in vivo trials; (iii) local and/or systemic statin use in EIP and/or ACP models; and (iv) quantitative evaluation of periodontal tissues (i.e., alveolar bone level/amount, attachment level, cementum formation, periodontal ligament formation). Sixteen studies in EIP models and 7 studies in ACP models evaluated simvastatin, atorvastatin or rosuvastatin. Thirteen of the EIP (81%) and 2 of the ACP (29%) studies presented significantly better results in terms of alveolar bone level/amount in favor of statins. Meta-analysis based on 14 EIP trials confirmed a significant benefit of local and systemic statin use (P < .001) in terms of alveolar bone level/amount; meta-regression revealed that statin type exhibited a significant effect (P = .014) in favor of atorvastatin. Three studies reported a significantly higher periodontal attachment level in favor of statin use (P < .001). Complete periodontal regeneration was never observed; furthermore, statins did not exert any apparent effect on cementum formation. Neither local nor systemic use of statins resulted in severe adverse effects. Statin use in periodontal indications has a positive effect on periodontal tissue parameters, supporting the positive results already observed in clinical trials. Nevertheless, not all statins available have been tested so far, and further research is needed to identify the maximum effective concentration/dose and optimal carrier.

Histochemical changes of occlusal surface enamel of permanent teeth, where dental caries is questionable vs sound enamel surfaces

AIM

This in vitro study was to classify questionable for caries occlusal surfaces (QCOS) of permanent teeth according to ICDAS codes 1, 2, and 3 and to compare them in terms of enamel mineral composition with the areas of sound tissue of the same tooth.

METHODS

Partially impacted human molars (60) extracted for therapeutic reasons with QCOS were used in the study, photographed via a polarised light microscope and classified according to the ICDAS II (into codes 1, 2, or 3). The crowns were embedded in clear self-cured acrylic resin and longitudinally sectioned at the levels of the characterised lesions and studied by SEM/EDX, to assess enamel mineral composition of the QCOS. Univariate and multivariate random effect regressions were used for Ca (wt%), P (wt%), and Ca/P (wt%).

RESULTS

The EDX analysis indicated changes in the Ca and P contents that were more prominent in ICDAS-II code 3 lesions compared to codes 1 and 2 lesions. In these lesions, Ca (wt%) and P (wt%) concentrations were significantly decreased (p = 0.01) in comparison with sound areas. Ca and P (wt%) contents were significantly lower (p = 0.02 and p = 0.01 respectively) for code 3 areas in comparison with codes 1 and 2 areas. Significantly higher (p = 0.01) Ca (wt%) and P (wt%) contents were found on sound areas compared to the lesion areas.

CONCLUSIONS

The enamel of occlusal surfaces of permanent teeth with ICDAS 1, 2, and 3 lesions was found to have different Ca/P compositions, necessitating further investigation on whether these altered surfaces might behave differently on etching preparation before fissure sealant placement, compared to sound surfaces.

Detection of TMPRSS2-ERG fusion gene in benign prostatic hyperplasia

The Ets-related gene fusions are among the most common molecular alterations in prostate cancer (PCa) and are detected in more than 50 % of PCas. Transmembrane protease serine 2 and Ets-related gene fusion (TMPRSS2-ERG) is the most frequently identified chimeric gene and has been associated with undifferentiated and invasive phenotypes. TMPRSS2-ERG has also been detected in prostate intraepithelial neoplasia (PIN) lesions and more rarely in benign prostatic hyperplasia (BPH) regions mainly in PCa-bearing glands. The possibility that the fusion TMPRSS2-ERG may be present in BPH samples in the absence of apparent PCa was addressed. Out of 115 BPH samples, three were found positive employing RT-PCR. The presence of the fusion gene was confirmed by FISH for these samples, and an additional four samples were found to carry the TMPRSS2-ERG fusion out of 43 tested by the later approach. The presence of the TMPRSS2-ERG fusion did not result in altered expression of 12 putative downstream targets. These findings indicate that TMPRSS2-ERG may or may not lead to PCa development.

Clonal chromosome-aberrations in fibrocystic breast disease-associated with increased risk of cancer

Short-term cultures of 29 samples of fibrocystic breast disease were cytogenetically analyzed. Clonal chromosome aberrations were found in six specimens, whereas the remaining 23 had a normal karyotype. Three of the abnormal samples displayed karyotypic anomalies previously associated with breast cancer, i.e., gain of Iq, trisomy 18 and cytogenetic multiclonality. Furthermore, all cytogenetically aberrant specimens had either proliferative disease without atypia or atypical hyperplasia, features of fibrocystic disease considered risk factors for subsequent breast cancer development. The cytogenetic similarities between breast carcinomas and proliferative fibrocystic breast disease add further support for classifying certain types of fibrocystic disease as a premalignant condition. Whether cytogenetically abnormal fibrocystic lesions are the ones that subsequently progress to cancer remains to be elucidated.

Forces and moments on posterior teeth generated by incisor intrusion biomechanics

OBJECTIVES

To comparatively evaluate the extrusive forces and torquing moments on the posterior dentition generated during anterior intrusion with different intrusion techniques in the maxillary and mandibular dental arch.

MATERIAL AND METHODS

Seven wire specimens were used for each of the following intrusive arches: Utility arch 0.016 x 0.016' Blue Elgiloy, Utility arch 0.017 x 0.025' TMA and Burstone Intrusion arch 0.017 x 0.025' TMA. The wires were inserted on bracketed dental arches constructed on maxillary Frasaco models, segmented mesially to the maxillary canines. Simulated intrusion from 0.0-3.0 mm was performed on the Orthodontic Measurement and Simulation System (OMSS). The forces and moments were recorded in all three planes of space at 0.1 mm increments and the values at 3.0 mm for all wires were used for all statistical evaluations. The data were analyzed, separately for the forces and moments, by means of two-way analysis of variance (ANOVA) with forces and moments serving as the dependent variables and intrusion technique and jaw (maxilla or mandible) as the independent variable. Post hoc multiple comparisons were performed using the Tukey test at .05 error rate.

RESULTS

The 0.016 x 0.016' Blue Elgiloy utility arch exerted the highest posterior extrusive forces, 15% higher than the 0.017 x 0.025' TMA utility and 40% higher in comparison with the 0.017 x 0.025' TMA Burstone intrusion arch.The lowest posterior moment in the sagittal plane was generated by the 0.017 x 0.025' TMA Burstone intrusion arch. The 0.016 x 0.016' Blue Elgiloy utility arch exerted 15% higher posterior moments and the 0.017 x 0.025' TMA utility 25% higher. Forces and moments were consistently larger for the mandible compared to the maxilla for the same intrusion technique.

CONCLUSIONS

The upper Burstone 0.017 x 0.025' TMA intrusion arch exerted the lowest forces/moments on posterior teeth. The highest forces were generated by the 0.016 x 0.016-inch Blue Elgiloy utility arch and the highest moments by the lower 0.017 x 0.025-inch TMA utility arch.

Long-term periodontal status of patients with mandibular lingual fixed retention

The purpose of this study was to evaluate the periodontal tissues of patients with mandibular fixed retention for long or short periods of time. A total of 64 individuals were selected for this study using the following inclusion criteria: long-term lingual fixed retention; identical type of lingual fixed retainer bonded with the same materials; no cavities, restorations, or fractures of the mandibular anterior teeth; absence of habits and occlusal interferences; and canine guidance bilaterally. The resultant sample comprised 32 patients (mean age 25 years) who had been in retention for a mean period of 9.65 years (range 9-11 years) and an equal number retained for a period between 3 and 6 months. Plaque, gingival, and calculus indices, probing pocket depth, marginal recession, and bone level at the mandibular six anterior teeth were recorded for both groups. Demographic, clinical, and radiographic data were investigated with conventional descriptive statistics. Comparisons of the different variables between the two participant groups (long- and short-term retention) were carried out using a Mann-Whitney test for indices (plaque, gingival, and calculus), and a Fisher's exact test (two sided) for the remaining variables. No significant difference was found with respect to the plaque and gingival indices and bone level between the two groups. The long-term group presented higher calculus accumulation, greater marginal recession, and increased probing depth (P < 0.05). The results of this study raise the question of the appropriateness of lingual fixed retainers as a standard retention plan for all patients regardless of their attitude to dental hygiene. They also emphasize the importance of individual variability and cautious application of retention protocols after a thorough consideration of issues related to the anatomy of tissues and oral hygiene.

Maxillary incisor torque with conventional and self-ligating brackets: a prospective clinical trial

OBJECTIVES

To test the hypothesis that the engagement mode of wire to bracket affects the buccolingual inclination of maxillary incisors in extraction and non-extraction treatment with self-ligating and conventional brackets.

DESIGN

A randomized clinical trial employing a random distribution of variables among the studied populations.

SETTING AND SAMPLE POPULATION

Private practice of one author. A total of 105 patients followed prospectively, were divided into two groups based on the inclusion of extraction in the treatment planning. These groups were further divided in two subgroups each, one receiving a self-ligating bracket and the other treated with a conventional Edgewise appliance of the same slot size and prescription.

EXPERIMENTAL VARIABLE

Difference in the buccolingual inclination of maxillary incisors before and after treatment with the two appliances across the two treatment groups (extraction and non-extraction).

OUTCOME MEASURE

Angular measurements of the Sella-Nasion and Nasion-A point to maxillary incisor axis.

RESULTS

No difference was found in the mean difference of the two angles measured for the two bracket groups studied.

CONCLUSION

Self-ligating brackets seem to be equally efficient in delivering torque to maxillary incisors relative to conventional brackets in extraction and non-extraction cases.

Assessment of clonal relationships in ipsilateral and bilateral multiple breast carcinomas by comparative genomic hybridisation and hierarchical clustering analysis

The issue of whether multiple, ipsilateral or bilateral, breast carcinomas represent multiple primary tumours or dissemination of a single carcinomatous process has been difficult to resolve, especially for individual patients. We have addressed the problem by comparative genomic hybridisation analysis of 26 tumours from 12 breast cancer patients with multiple ipsilateral and/or bilateral carcinoma lesions. Genomic imbalances were detected in 25 of the 26 (96%) tumours. Using the genomic imbalances detected in these 26 lesions as well as those previously found by us in an independent series of 35 unifocal breast carcinomas, we compared a probabilistic model for likelihood of independence with unsupervised hierarchical clustering methodologies to determine the clonal relatedness of multiple tumours in breast cancer patients. We conclude that CGH analysis of multiple breast carcinomas followed by unsupervised hierarchical clustering of the genomic imbalances is more reliable than previous criteria to determine the tumours’ clonal relationship in individual patients, that most ipsilateral breast carcinomas arise through intramammary spreading of a single breast cancer, and that most patients with bilateral breast carcinomas have two different diseases.

CRD-BP: a c-Myc mRNA stabilizing protein with an oncofetal pattern of expression

The Coding Region Determinant-Binding Protein (CRD-BP) is an RRM and KH-domain-containing protein that recognizes specifically at least three RNAs. It binds to one of the two c-myc mRNA instability elements, to the 5'Un Translated Region (UTR) of the leader 3 IGF-II mRNA and to the oncofetal H19 RNA. CRD-BP has been assigned a role in stabilizing c-myc mRNA by preventing its endonucleolytic cleavage and in repressing the translation of the leader 3 IGF-II mRNA, the major embryonic species of this message. CRD-BP is normally expressed only in fetal tissues. However, its expression is detected in primary tumors and transformed cell lines of different origins. The vast majority of colon (80%) and breast (60%) tumors and sarcomas (73%) express CRD-BP whereas in other tumor types, for example prostate carcinomas, its expression is rare. CRD-BP expression has also been detected in benign tumors such as breast fibroadenomas, meningiomas and other benign mesenchymal tumors, implying a role for this gene in abnormal cell proliferation. In breast carcinomas, CRD-BP expression and or gene copy number gains in the region encompassing the c-myc locus were detected in approximately 75% of tumors, implying that the deregulated expression of c-myc may be more widespread than previously believed. Infiltrated lymph nodes, corresponding to CRD-BP-positive primary tumors, were also found positive indicating that monitoring for CRD-BP could prove useful for the detection and monitoring of disseminated disease.

Germ line BRCA1 & BRCA2 mutations in Greek breast/ovarian cancer families: 5382insC is the most frequent mutation observed

BRCA1 and BRCA2 genes were screened for loss-of-function mutations in a series of 85 patients having at least one first- or second-degree relative affected by breast and/or ovarian cancer. All BRCA1 exons and BRCA2 exons 10 and 11 were screened with a combination of methods including SSCP, PTT and direct sequencing. We have found disease-associated mutations in 14 families (16.5%), eleven in BRCA1 and three in BRCA2. The known founder mutation 5382insC of BRCA1 was identified in seven unrelated families. The other mutations identified include the non-sense R1751X, the splice junction variant 5586G>A of BRCA1 and three frameshifts, 2024del5, 3034del4, and 6631del5, of BRCA2. Nine out of these 14 families had a family history of three or more breast/ovarian cancer cases. A large number of polymorphic or unclassified variants is also reported. Combined with our previously published data 5382insC was found in nine out of 20 families (45%), suggesting that this mutation may represent a common founder mutation in the Greek population.

C-MYC and IGF-II mRNA-binding protein (CRD-BP/IMP-1) in benign and malignant mesenchymal tumors

Mouse coding region determinant-binding (mCRD-BP) and human IGF-II mRNA-binding 1 (hIMP-1) proteins are orthologous mRNA-binding proteins that recognize c-myc and IGF-II mRNA, respectively, and regulate their expression posttranscriptionally. Here, we confirm that human CRD-BP/IMP-1 binds to c-myc mRNA and that it is predominantly expressed in fetal tissues. Moreover, hCRD-BP/IMP-1 expression was detected in cell lines of neoplastic origin and in selected primary tumors. In a series of 33 malignant and 10 benign mesenchymal tumors, 73% and 40%, respectively, were found to express hCRD-BP/IMP-1. In particular, expression was significant in 14 Ewing's sarcomas, all of which were positive. The data suggest that hCRD-BP/IMP-1 plays a role in abnormal cell proliferation in mesenchymal tumors.

Are some breast carcinomas polyclonal in origin?

This editorial comments on the important study by Going et al. published in the present issue of the Journal [1]. Using a molecular genetic assay based on the X-chromosome inactivation principle, they found that 4 out of 12 breast carcinomas examined exhibited what the authors call "clonal mosaicism" that is, two or more monoclonal samples were mosaic (polyclonal) in respect of X chromosome inactivation between separate, morphologically homogeneous tumour areas. The authors very carefully discuss potential methodological errors that could have led to this surprising finding, which seems to run counter to the almost unanimously held conviction that carcinomas are monoclonal in origin, but none of these potential errors would explain the results. As often in such situations, the authors prudently state that further studies using independent analytical techniques are necessary to find out whether a significant proportion of mammary carcinomas are indeed polyclonal. However, there already exists a substantial body of evidence from cytogenetic studies of breast cancers indicating that many of them are polyclonal. Although there is still room for interpretation and some doubt remains as to exactly which role should be ascribed to the observed clonal heterogeneity in our models of carcinogenesis, it seems obvious that more attention than before ought to be paid to this now well documented fact.

Evaluation of breast cancer polyclonality by combined chromosome banding and comparative genomic hybridization analysis

Cytogenetically unrelated clones have been detected by chromosome banding analysis in many breast carcinomas. Because these karyotypic studies were performed on short-term cultured samples, it may be argued that in vitro selection occurred or that small clones may have arisen during culturing. To address this issue, we analyzed 37 breast carcinomas by G-banding and comparative genomic hybridization (CGH), a fluorescent in situ hybridization--based screening technique that does not require culturing or tumor metaphases. All but two of the 37 karyotypically abnormal cases presented copy number changes by CGH. The picture of genomic alterations revealed by the two techniques overlapped only partly. Sometimes the CGH analysis revealed genomic imbalances that belonged to cell populations not picked up by the cytogenetic analysis and in other cases, especially when the karyotypes had many markers and chromosomes with additional material of unknown origin, CGH gave a more reliable overall picture of the copy number gains and losses. However, besides sometimes revealing cell populations with balanced chromosome aberrations or unbalanced changes that nevertheless remained undetected by CGH, G-banding analysis was essential to understand how the genomic imbalances arose in the many cases in which both techniques detected the same clonal abnormalities. Furthermore, because CGH pictures only imbalances present in a significant proportion of the test sample, the very detection by this technique of imbalances belonging to apparently small, cytogenetically unrelated clones of cells proves that these clones must have been present in vivo. This constitutes compelling evidence that the cytogenetic polyclonality observed after short-term culturing of breast carcinomas is not an artifact.

High frequency of clonal chromosome abnormalities in prostatic neoplasms sampled by prostatectomy or ultrasound-guided needle biopsy

Cancer of the prostate remains poorly characterized cytogenetically. This is due in part to methodological problems and in part to the paucity of radical prostatectomies, until now the main source of material for cytogenetic analyses. We have improved existing techniques for the culturing of prostatic neoplasms removed by radical prostatectomy or sampled by ultrasound-guided needle biopsy. Successful short-term cultures were obtained from all 10 prostatectomy samples and from all 10 ultrasound-guided needle biopsies, always with a pure epithelial morphology. Of the 19 cases yielding a sufficient number of high-quality metaphases for chromosome banding analysis, the single atypical epithelial hyperplasia had a normal karyotype, whereas both prostatic intraepithelial neoplasias and 12 of 16 (75%) invasive carcinomas were shown to have clonal abnormalities. Ten of the 12 (83%) karyotypically abnormal invasive carcinomas presented structural chromosomal rearrangements. A recurrent deletion, del(10)(p13), was seen in three tumors; in one of them the terminal nature of the deletion was confirmed by two-color FISH. A del(17)(p11) was seen in one PIN lesion, but since the analysis of exons 4-8 of the TP53 tumor suppressor gene revealed no mutations, there probably was no inactivation of the second TP53 allele. Our study thus leads to the following main conclusions. First, better culturing methods allow the detection of abnormal karyotypes in a much higher percentage of prostatic neoplasms than has hitherto been possible. Second, ultrasound-guided needle biopsies of prostatic neoplasms are a sufficient source of material for cytogenetic analysis. Third, a terminal deletion of the short arm of chromosome 10, del(10)(p13), seems to identify a subgroup of prostatic cancer.

Cytogenetic heterogeneity and clonal evolution in synchronous bilateral breast carcinomas and their lymph node metastases from a male patient without any detectable BRCA2 germline mutation

Two synchronous bilateral breast carcinomas and their matched lymph node metastases from a 70-year-old man were cytogenetically analyzed. All four tumors were near-diploid, and except for the primary tumor from the right breast, had a 45,X,-Y clone in common. The loss of the Y chromosome was, however, common to all four tumors, whereas metaphase cells from peripheral blood lymphocytes showed a normal 46, XY chromosome complement. The primary tumor from the right breast was monoclonal, with loss of the Y chromosome and gain of 1q, whereas its metastasis had two related clones: the 45,X,-Y clone, and the other a more complex version of the clone in the primary tumor, with inv(3), -14, and del(16)(q13) as additional changes. The primary tumor from the left breast was polyclonal with three unrelated clones: 45,X,-Y/45,XY,-18/47,XY,+20, two of which were present in its metastasis. DNA flow cytometric studies showed diploidy for both primary tumors. No mutation in the BRCA2 gene was found on analysis of DNA from peripheral blood lymphocytes. The present findings show that del(16)(q13) is a recurrent finding among male breast carcinomas and that some of the primary cytogenetic abnormalities, as well as the pattern of chromosomal changes during the progression of sporadic breast carcinoma in the male, are similar to those in the female. In addition, the loss of the Y chromosome in the tumors but not in peripheral blood lymphocytes, suggests a possible role for this abnormality in the pathogenesis of male breast carcinoma.

Spectral karyotyping and chromosome banding studies of primary breast carcinomas and their lymph node metastases

Three primary breast tumors and their lymph node metastases were characterized by G-banding, spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH). In each case, the karyotypic abnormalities detected were similar in the primary tumor and its matched metastasis. Two of the pairs had near-diploid karyotypes with three to four chromosomal aberrations, whereas the third pair had a near-pentaploid chromosome content and many marker chromosomes in the primary tumor and a near-tetraploid chromosome number with almost the same marker chromosomes in the metastasis. SKY and FISH confirmed the karyotypic similarities between the primary tumors and their metastases and, in addition, improved the identification and characterization of marker chromosomes. One of the tumor pairs with near-diploid karyotypes had gain of 8q, 16q, and 17q, whereas the other had gain of 1q and chromosome 8 material in the form of ring chromosomes. The third pair had more complex chromosomal translocations and numerical changes resulting in net gain of material from chromosomes X, 1, 2, 6, 7, 14, 16, 19, and 20, and chromosome arms 8q and 11q, as well as net loss of material from chromosomes 3, 13, 18, 21, and 22. The present study underscores the need to combine conventional chromosome banding and molecular cytogenetic techniques in the cytogenetic analysis of solid tumors.

Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts

Aneurysmal bone cyst (ABC) is a benign bone lesion for which no previous cytogenetic data exist. We describe the finding of clonal chromosome aberrations in three tumors; two had a t(16;17)(q22;p13) as the sole anomaly, and the third had a del(16)(q22) as the only change. These findings show that somatic mutations contribute to the development of ABC and furthermore indicate that bands 16q22 and 17p13 may harbor genes of importance in this process.

Karyotypic evolution in breast carcinomas with i(1)(q10) and der(1;16)(q10;p10) as the primary chromosome abnormality

The pattern of clonal karyotypic evolution in breast carcinomas carrying an i(1q) or a der(1;16)(q10;p10) as the primary chromosome abnormality was assessed in a series of 42 tumors, including 8 described here for the first time, with either or both (3 tumors) of them defining cytogenetic features. Evidence of clonal evolution was seen in somewhat more than half of all cases in both subgroups. The secondarily acquired aberrations appeared to be nonrandom in distribution. This was especially so for structural rearrangements of 11q leading to loss of material from this arm, which were clearly more common in both subgroups than in karyotypically abnormal breast carcinomas in general. Other deviations from random were less certain but seemed to include the frequent occurrence of +20 in tumors with i(1q) and +7 in tumors with der(1;16)(q10;p10). That differences were observed between i(1q) carcinomas and der(1;16)(q10;p10) carcinomas with regard to their patterns of clonal evolution hints that the pathogenetic effect of the primary change in these two situations may be more than the mere gain of an extra copy of 1q.

Different patterns of chromosomal imbalances in metastasising and non-metastasising primary breast carcinomas

In an attempt to identify chromosomal abnormalities that may be associated with a metastatic phenotype, we investigated the pattern of chromosomal gains and losses in 66 node-positive and 63 node-negative primary breast carcinomas. For both subgroups of tumours, losses were more common than gains and the losses were most often the result of structural aberrations. The exceptions were the long arm of chromosome 1, and chromosomes 7, 8, 12, 18 and 20, which were more often gained than lost. Node-negative tumours were preferentially characterised by loss of 6q10-21 and loss of 16q, whereas loss of chromosome 18 was significant for node-positive tumours. Other aberrations that tended to be associated with one of the phenotypes, though not statistically significant, were gain of chromosome 18 and loss of chromosome 10 in node-negative tumours, and gain of chromosome 14 and loss of 12p in node-positive tumours. Our data show that there are differences among the genetic lesions present in node-negative and node-positive breast tumours. Int. J. Cancer (Pred. Oncol.) 84:370-375, 1999.

Different patterns of chromosomal imbalances in metastasising and non-metastasising primary breast carcinomas

In an attempt to identify chromosomal abnormalities that may be associated with a metastatic phenotype, we investigated the pattern of chromosomal gains and losses in 66 node-positive and 63 node-negative primary breast carcinomas. For both subgroups of tumours, losses were more common than gains and the losses were most often the result of structural aberrations. The exceptions were the long arm of chromosome 1, and chromosomes 7, 8, 12, 18 and 20, which were more often gained than lost. Node-negative tumours were preferentially characterised by loss of 6q10-21 and loss of 16q, whereas loss of chromosome 18 was significant for node-positive tumours. Other aberrations that tended to be associated with one of the phenotypes, though not statistically significant, were gain of chromosome 18 and loss of chromosome 10 in node-negative tumours, and gain of chromosome 14 and loss of 12p in node-positive tumours. Our data show that there are differences among the genetic lesions present in node-negative and node-positive breast tumours. Int. J. Cancer (Pred. Oncol.) 84:370-375, 1999.

Multiple polysomies in breast carcinomas: preferential gain of chromosomes 1, 5, 6, 7, 12, 16, 17, 18, and 19

Chromosome G-banding analysis of metaphase cells from 16 primary breast carcinomas revealed the presence of multiple polysomies in near-diploid as well as in polyploid cells. Chromosome 17 was preferentially gained in 7 tumors, followed in frequency by chromosomes 1, 12, and 19 (5 tumors each), and chromosomes 5, 6, 7, 16, and 18 (4 tumors each). Eleven of the 16 carcinomas had, apart from the clones exhibiting the numerical gains, other unrelated clones. Nine of these 11 cases had clones with structural chromosome aberrations, 5 of which had structural aberrations involving the short arm of chromosome 3. The biologic significance, if any, of this seemingly nonrandom coexistence of multiple polysomies with structural aberrations of 3p is at present not known. The pattern of numerical chromosome aberrations observed in the present study is comparable to previous results from fluorescence in situ hybridization (FISH) studies, with the use of centromeric probes on interphase cells. However, unlike FISH studies, which have been focused on chromosomes 1, 3, 7, 8, 11, 16, and 17, the cytogenetic results reveal that other chromosomes also may be nonrandomly gained as part of multiple polysomies in breast carcinomas. In addition, the tumors with multiple polysomies were generally of high histologic grade and with metastasis to axillary lymph nodes, suggesting that multiple wholechromosome gains may be a pathway of genetic evolution or progression or both in some breast carcinomas.

Chromosomal aberrations in breast cancer: a comparison between cytogenetics and comparative genomic hybridization

The analysis of chromosomal imbalances in solid tumors using comparative genetic hybridization (CGH) has gained much attention. A survey of the literature suggests that CGH is more sensitive in detecting copy number aberrations than is karyotyping, although careful comparisons between CGH and cytogenetics have not been performed. Here, we compared cytogenetics and CGH in 29 invasive breast cancers after converting the karyotypes into net copy number gains and losses. We found 15 tumors (56%) with a significant agreement between the two methods and 12 tumors (44%) where the methods were in disagreement (two cases failed CGH analysis). Interestingly, in 13 of the 15 tumors where the two methods were concordant, there was also a strong correlation between chromosome index and DNA index by flow cytometry. In the opposite situation, i.e., when chromosome and DNA indices were not matching, there was disagreement between cytogenetics and CGH in 10 of the 12 tumors. Of the discordant cases, all except one had a "simple" abnormal karyotype. Unresolved chromosomal aberrations (marker chromosomes, homogeneously staining regions, double minutes) could not completely explain the differences between CGH and karyotyping. A likely explanation for the discrepancies is that the methods analyzed different cell populations. Gains and losses found by CGH represented the predominant (often aneuploid) clone, whereas the abnormal, near-diploid karyotypes represented minor cell clone(s), which, for unknown reasons, had a growth advantage in vitro.