Genetic landscape and deregulated pathways in B-cell lymphoid malignancies.

With the introduction of next-generation sequencing, the genetic landscape of the complex group of B-cell lymphoid malignancies has rapidly been unravelled in recent years. This has provided important information about recurrent genetic events and identified key pathways deregulated in each lymphoma subtype. In parallel, there has been intense search and development of novel types of targeted therapy that 'hit' central mechanisms in lymphoma pathobiology, such as BTK, PI3K or BCL2 inhibitors. In this review, we will outline the current view of the genetic landscape of selected entities: follicular lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma, chronic lymphocytic leukaemia and marginal zone lymphoma. We will detail recurrent alterations affecting important signalling pathways, that is the B-cell receptor/NF-κB pathway, NOTCH signalling, JAK-STAT signalling, p53/DNA damage response, apoptosis and cell cycle regulation, as well as other perhaps unexpected cellular processes, such as immune regulation, cell migration, epigenetic regulation and RNA processing. Whilst many of these pathways/processes are commonly altered in different lymphoid tumors, albeit at varying frequencies, others are preferentially targeted in selected B-cell malignancies. Some of these genetic lesions are either involved in disease ontogeny or linked to the evolution of each disease and/or specific clinicobiological features, and some of them have been demonstrated to have prognostic and even predictive impact. Future work is especially needed to understand the therapy-resistant disease, particularly in patients treated with targeted therapy, and to identify novel targets and therapeutic strategies in order to realize true precision medicine in this clinically heterogeneous patient group.

Somatic CALR mutations in myeloproliferative neoplasms with nonmutated JAK2.

BACKGROUND: Somatic mutations in the Janus kinase 2 gene (JAK2) occur in many myeloproliferative neoplasms, but the molecular pathogenesis of myeloproliferative neoplasms with nonmutated JAK2 is obscure, and the diagnosis of these neoplasms remains a challenge. METHODS: We performed exome sequencing of samples obtained from 151 patients with myeloproliferative neoplasms. The mutation status of the gene encoding calreticulin (CALR) was assessed in an additional 1345 hematologic cancers, 1517 other cancers, and 550 controls. We established phylogenetic trees using hematopoietic colonies. We assessed calreticulin subcellular localization using immunofluorescence and flow cytometry. RESULTS: Exome sequencing identified 1498 mutations in 151 patients, with medians of 6.5, 6.5, and 13.0 mutations per patient in samples of polycythemia vera, essential thrombocythemia, and myelofibrosis, respectively. Somatic CALR mutations were found in 70 to 84% of samples of myeloproliferative neoplasms with nonmutated JAK2, in 8% of myelodysplasia samples, in occasional samples of other myeloid cancers, and in none of the other cancers. A total of 148 CALR mutations were identified with 19 distinct variants. Mutations were located in exon 9 and generated a +1 base-pair frameshift, which would result in a mutant protein with a novel C-terminal. Mutant calreticulin was observed in the endoplasmic reticulum without increased cell-surface or Golgi accumulation. Patients with myeloproliferative neoplasms carrying CALR mutations presented with higher platelet counts and lower hemoglobin levels than patients with mutated JAK2. Mutation of CALR was detected in hematopoietic stem and progenitor cells. Clonal analyses showed CALR mutations in the earliest phylogenetic node, a finding consistent with its role as an initiating mutation in some patients. CONCLUSIONS: Somatic mutations in the endoplasmic reticulum chaperone CALR were found in a majority of patients with myeloproliferative neoplasms with nonmutated JAK2. (Funded by the Kay Kendall Leukaemia Fund and others.).

[Prevalence of dentinal hypersensitivity and related factors in Chinese urban adults].

Objective: To assess the prevalence of dentinal hypersensitivity (DH) and related factors in urban adults in China. Methods: The study was designed as an observational, cross-sectional epidemiological study carried out in adults aged 18-69 years old in seven cities (Beijing, Shanghai, Wuhan, Chengdu, Xi'an, Guangzhou, and Harbin) of China. The study was conducted from March 2021 to May 2023. Patients were required to complete a questionnaire regarding the subjects' socio-economic factors, dietary behavior, oral health behavior and personal antecedent factors. DH was clinically diagnosed by judging whether the tooth cold air stimulation provoked DH or not, and recorded by investigator pain rating Schiff score. Compare the findings of six cities (Harbin excluded) with a similar study conducted in 2008. Results: In total, 11 622 subjects from seven cities in China participated the study. Fifty two point two percent (6 072/11 622) of subjects reported DH in questionnaire, 36.7% (4 266/11 622) of subjects reported experiencing DH in response to cold air stimulation for at least one study tooth. Risk factors including age, sex, city, toothbrush method and acid reflux showed marked associations with DH (P<0.05). The prevalence of DH of urban residents in six cities (Harbin excluded) was 33.7% (3 335/9 882), higher than that in 2008 [29.7%(2 354/7 939)]. Conclusions: Overall, DH was common among urban adults in China and the prevalence increased in recent years. Better understanding of DH and its associated factors should be considered in its prevention and management by dental professionals.

EGILS consensus report. Gastric extranodal marginal zone B-cell lymphoma of MALT.

This consensus report of the EGILS (European Gastro-Intestinal Lymphoma Study) group includes recommendations on the management of gastric extranodal marginal zone B-cell lymphoma of MALT. They are based on data from the literature and on intensive discussions and votings of the experts during their annual meetings.

The prevalence of and risk factors for non-carious cervical lesions in adults in Hubei Province, China.

OBJECTIVES: To describe the prevalence of non-carious cervical lesions (NCCLs) and to assess the relative affects of risk factors on NCCLs in middle-aged and elderly people in Hubei Province, China. DESIGN: A sample of 2,160 adults, aged 35-44 years and 65-74 years and balanced by age, gender, and urbanization, participated in the cross sectional epidemiological survey. Non-carious cervical lesions were examined using a modified Tooth Wear Index. Data were collected based on structured questionnaires that assessed general information as well as oral health. RESULTS: The prevalence of non-carious cervical lesions was 38.8% for 35-44-year-olds and 56.6% for 65-74-year-olds. The first premolars, canines, and second premolars showed the highest prevalence of lesions, while the second molars demonstrated the least. Several risk factors such as age (OR = 2.45, p < 0.001), location (OR = 1.68, p = 0.001), frequency of toothbrushing (OR = 1.33, p = 0.016), bruxism (OR = 1.37, p < 0.001), and family income (OR = 1.44, p < 0.001) were found to be associated with lesion occurrence. CONCLUSIONS: The prevalence of non-carious cervical lesions was relatively high in the middle-aged and elderly persons in China and was also associated with socio-behavioural risk factors.

Continual monitoring of intraepithelial lymphocyte immunophenotype and clonality is more important than snapshot analysis in the surveillance of refractory coeliac disease.

OBJECTIVE: An aberrant immunophenotype and monoclonality of intraepithelial lymphocytes (IELs) are frequently found in refractory coeliac disease (RCD). However, the utility of continual monitoring of IEL immunophenotype and clonality in the surveillance of RCD remains to be studied. DESIGN: The diagnostic and follow-up biopsies from 33 patients with CD, 7 with suspected RCD, 41 with RCD and 20 with enteropathy-associated T cell lymphoma (EATL) (including 11 evolved from RCD) were investigated by CD3epsilon/CD8 double immunohistochemistry and PCR-based clonality analysis of the rearranged T cell receptor (TCR) genes. RESULTS: An aberrant immunophenotype (CD3epsilon(+)CD8(-) IELs > or =40%) and monoclonality were detected occasionally in CD biopsies, either transiently in patients with CD not compliant with a gluten-free diet or in those who subsequently developed suspected RCD, RCD or EATL. In contrast, the aberrant immunophenotype and monoclonality were found in 30 of 41 (73%) and 24 of 37 (65%) biopsies, respectively, at the time of RCD diagnosis. Among the patients with RCD who did not show these abnormalities in their diagnostic biopsies, 8 of 10 (80%) and 5 of 11 (45%) cases gained an aberrant immunophenotype and monoclonality, respectively, during follow-up. Irrespective of whether detected in diagnostic or follow-up biopsies, persistence of both abnormalities was characteristic of RCD. Importantly, the presence of concurrent persistent monoclonality and aberrant immunophenotype, especially > or =80% CD3epsilon(+)CD8(-) IELs, was a strong predictor of EATL development in patients with RCD (p=0.001). CONCLUSIONS: Continual monitoring of both immunophenotype and clonality of IELs is more important than snapshot analysis for RCD diagnosis and follow-up, and could provide a useful tool for surveillance of patients at risk of EATL.

A20 deletion is associated with copy number gain at the TNFA/B/C locus and occurs preferentially in translocation-negative MALT lymphoma of the ocular adnexa and salivary glands.

The genetic basis of MALT lymphoma is largely unknown. Characteristic chromosomal translocations are frequently associated with gastric and pulmonary cases, but are rare at other sites. We compared the genetic profiles of 33 ocular adnexal and 25 pulmonary MALT lymphomas by 1 Mb array-comparative genomic hybridization (CGH) and revealed recurrent 6q23 losses and 6p21.2-6p22.1 gains exclusive to ocular cases. High-resolution chromosome 6 tile-path array-CGH identified NF-kappaB inhibitor A20 as the target of 6q23.3 deletion and TNFA/B/C locus as a putative target of 6p21.2-22.1 gain. Interphase fluorescence in situ hybridization showed that A20 deletion occurred in MALT lymphoma of the ocular adnexa (8/42=19%), salivary gland (2/24=8%), thyroid (1/9=11%) and liver (1/2), but not in the lung (26), stomach (45) and skin (13). Homozygous deletion was observed in three cases. A20 deletion and TNFA/B/C gain were significantly associated (p<0.001) and exclusively found in cases without characteristic translocation. In ocular cases, A20 deletion was associated with concurrent involvement of different adnexal tissues or extraocular sites at diagnosis (p=0.007), a higher proportion of relapse (67% versus 37%) and a shorter relapse-free survival (p=0.033). A20 deletion and gain at TNFA/B/C locus may thus play an important role in the development of translocation-negative MALT lymphoma.

Accelerated aging effects on color, microhardness and microstructure of ICON resin infiltration.

OBJECTIVE: Infiltration resins provide an ideal treatment alternative for white spot lesions on teeth. The icon infiltrant has been widely used as a dental material for a few years, but there are some studies on the in vitro accelerated aging process and the change of hardness and microstructure on this material. The innovation of this work is to aim at investigating characteristics associated with this infiltrant resin and comparing the Icon infiltrant with universal Filtek Z350 and flowable Filtek Z350 resins when exposed to artificial accelerated aging. MATERIALS AND METHODS: Materials were prepared as disc-shaped specimens sized to 12 mm × 2.2 mm and were aged through exposure to 150 kJ/m2 in an artificial accelerated aging machine. Two-time points, 24 h after aging and 96 h after aging, were selected for evaluation in the following trials. The morphology was observed using a scanning electron microscopy. The standard CIEL*a*b* color system was employed for color measurements. Microhardness of all specimens was analyzed by a Knoop indenter. Chemical components were examined by Fourier transform infrared spectroscopy. RESULTS: Compared with universal Z350 and flowable Z350, the ICON infiltrant resin presented a uniform, slightly scratched surface before and after accelerated aging. The 24 h artificial accelerated aging of the three investigated materials resulted in acceptable color alterations, a ΔE* range of 2.52±0.63 for universal Z350, 2.43±0.59 for flowable Z350 and 3.31±0.32 for ICON. After 96 h aging, significant color changes were noted for universal Z350 (7.51±0.63) and ICON (4.70±0.69). The ICON infiltrant displayed reduced microhardness when compared to universal Z350 and flowable Z350. The absorption peaks of the chemical bonds were significantly altered after the accelerated aging process. CONCLUSIONS: Composed in a triethylene glycol dimethacrylate (TEGDMA) monomer-based network, the color stability and microhardness of the infiltrant resin provided suitable material for treating white spot lesions (WSLs), yet presented susceptibility under accelerated aging. Thus, osmotic resin therapy has strict limitations to be most effective.

Ocular adnexal MALT lymphoma: an intriguing model for antigen-driven lymphomagenesis and microbial-targeted therapy.

Non-Hodgkin's lymphomas constitute one half of malignancies arising in the orbit and the ocular adnexae. Mucosa-associated lymphoid tissue (MALT)-type lymphoma is the most common histological category in this anatomic region. The incidence of ocular adnexal lymphoma of mucosa-associated lymphoid tissue-type (OAML) is increasing and recent studies offered new relevant insights in molecular, pathogenetic and therapeutic issues on these neoplasms. A pathogenetic model of antigen-driven lymphoproliferation similar to that reported for Helicobacter pylori-related gastric MALT lymphomas has been hypothesized for OAML. This notion is supported by the association between OAML and Chlamydophila psittaci infection, an association that is of likely pathogenetic relevance and may influence both the biological behavior and the therapeutic management of these neoplasms. However, this association displays evident geographical variability indicating that other etiopathogenic agents could be involved. These recent acquisitions coupled with the occurrence of chromosomal translocations and other genetic alterations, as well as additional risk factors like autoimmune disorders have contributed to render OAML an exciting challenge for a broad group of physicians and scientists. OAML is an indolent and rarely lethal malignancy that, in selected patients, can be managed with observation alone. Lymphomatous lesions are frequently responsible for symptoms affecting patient's quality of life, requiring, therefore, immediate treatment. Several therapeutic strategies are available, often associated with relevant side-effects. However, the therapeutic choice in OAML is not supported by consolidated evidence due to the lack of prospective trials. In this review, we analyze the most relevant biological, molecular, pathological and clinical features of OAML and propose some therapeutic guidelines for patients affected by this malignancy.

Perforation predicts poor prognosis in patients with primary intestinal diffuse large B-cell lymphoma.

AIMS: To elucidate the clinicopathological features and prognostic factors of primary intestinal diffuse large B-cell lymphoma (PI-DLBL). METHODS AND RESULTS: Archival tissues from 30 tumours were used for tissue microarray construction, immunohistochemistry and interphase fluorescence in situ hybridization for chromosomal translocation. The M:F ratio was 1.7:1, with a median age of 60 years. The ileum and ileocaecum were most frequently involved (40% each). Fourteen (47%) were at stage I(E) disease, 15 (50%) at stage II(E). Five (17%) tumours were perforated at presentation. The tumours expressed Bcl-6 (73%), MUM1 (70%), Bcl-2 (67%) and CD10 (23%). Nine (30%) were classified as germinal centre B-cell (GCB) phenotype and 21 non-GCB. Eight of 30 (27%), 7/30 (23%) and 2/29 (7%) cases were positive for rearrangements involving IGH, BCL6, and C-MYC loci, respectively, whereas all cases were negative for BCL2 and CCND1 translocation. Perforation was a poor prognostic indicator, with a hazard ratio of tumour-related death at 8.75 (P = 0.001). The differentiation antigens, GCB versus non-GCB phenotype, or lymphoma-associated translocations were of no prognostic significance. CONCLUSIONS: We found a higher rate of perforation and lower frequency of GCB phenotype in PI-DLBL in Taiwan compared with other geographical areas; perforation is a poor prognostic indicator.

Mantle cell lymphoma with aberrant expression of CD10.

AIMS: Morphological, immunophenotypic and genetic heterogeneity amongst mantle cell lymphomas (MCLs) can lead to difficulties in diagnosis and management. The aim was to describe the clinical and pathological features of MCLs with aberrant expression of CD10. METHODS AND RESULTS: Of 17 specimens from 13 patients, 14 expressed CD10 and three (presenting before or after a CD10+ specimen) did not. All expressed cyclin D1 and carried the t(11;14)(q13;q32)/CCND1-IGH translocation. Similar to non-selected MCL patients, most patients had disseminated disease and an adverse clinical course. Five specimens showed pleomorphic blastoid morphology and blastoid transformation was associated with a change in phenotype, including gain or loss of CD10. Additional phenotypic variations likely to cause diagnostic difficulty were present in eight specimens: five were CD5- and five (all CD10+) expressed Bcl-6. One Bcl-6+ case carried a BCL-6 translocation and three others had extra copies of the BCL-6 gene. Sequence analysis of the immunoglobulin heavy chain variable region in five cases showed only one to have low-level somatic mutation, indicating that they did not arise from germinal centre B cells. CONCLUSIONS: Expression of CD10 by MCL is often associated with other variant morphological, immunophenotypic or genetic features, but does not reflect derivation from germinal centre B cells.

Sporadic paediatric and adult Burkitt lymphomas share similar phenotypic and genotypic features.

AIMS: To characterize the clinicopathological features of sporadic Burkitt lymphoma (BL). METHODS AND RESULTS: A retrospective study of 17 paediatric and 14 adult BLs with history and histopathology review, immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization (EBER) and fluorescence in situ hybridization. There was no statistically significant difference in gender, frequency of central nervous system (CNS) involvement and leukaemic change at presentation, or frequency of CD10+/Bcl-2-/Bcl-6+ (88% versus 86%), Ki67 labelling index, EBER (24% versus 21%), or C-MYC translocation (100% versus 92%) between paediatric and adult tumours. Correct pretreatment diagnoses were made in 13/17 (76%) paediatric and in 9/14 (64%) adult tumours. Twenty-eight patients received chemotherapy including 13/16 (81%) paediatric and 3/12 (25%) adult patients with appropriate regimens; 16 (57%) received CNS prophylaxis. The 1- and 5-year overall survival (OS) rates for paediatric patients were 80% and 50%, respectively, whereas 1-year OS for adults was 15%. CONCLUSIONS: Sporadic paediatric and adult BLs were phenotypically and genotypically similar. The significant prognosticators were age (P = 0.001), with or without CNS prophylaxis (P = 0.004), and CNS involvement (P = 0.008) and leukaemic change (P = 0.019) in disease course. The poor outcome in adult patients might be related to incorrect diagnosis and inappropriate treatment.

A two-year randomized clinical trial of chlorhexidine varnish on dental caries in Chinese preschool children.

The objective of this study was to assess the effect of six-monthly professional applications of chlorhexidine varnish on the prevention of dental caries in primary molars in Chinese preschool children. In a double-blinded, randomized, placebo-controlled clinical trial, 334 children aged 4-5 years were randomly divided into two groups. Children in the test group received six-monthly applications of a 40% chlorhexidine varnish, and the control children received a placebo varnish. Caries status of the children was assessed by two calibrated examiners at baseline and after 24 months, according to criteria recommended by the World Health Organization. The two-year mean caries increments in the test and the control group children were 1.0 and 1.6 decayed, missing, or filled molar surfaces (dmfs-molar), respectively, a 37.3% reduction (t test, p = 0.036). No side-effects were found. It was concluded that six-monthly applications of chlorhexidine varnish were effective in reducing the incidence of dental caries in primary molars.

Templated nucleotide addition and immunoglobulin JH-gene utilization in t(11;14) junctions: implications for the mechanism of translocation and the origin of mantle cell lymphoma.

The t(11;14)(q13;q32) between the BCL-1 and immunoglobulin heavy chain gene (IgH) loci in mantle cell lymphoma (MCL) are believed to be mediated by the mechanism of V(D)J recombination similar to the t(14; 18) in follicular lymphoma (FL). We have recently shown that the t(14;18) event creates staggered double-strand breaks in the BCL-2 locus, and that the t(14;18) junctions contain templated nucleotide insertions (T-nucleotides; U. Jäger et al., Blood, 95: 3520-3529, 2000). Reasoning that the earlier (pregerminal center) B-cell origin of MCL might be reflected in a different molecular structure of the chromosomal breakpoints, we PCR-amplified diagnostic samples from 93 patients. Thirty-six samples (39%) were positive for the direct (BCL-1/J(H)) and 23 for both direct and reciprocal (D(H)/BCL-1) junctions. The breaks on chromosome 14 exhibited features of V(D)J-mediated recombination as shown by D(H) and J(H) coding end processing. However, duplications of BCL-1 sequences in 39% of the 23 patients indicate staggered double-strand breaks in the major translocation cluster region (MTC). This is incompatible with V(D)J recombination and indicates a different mechanism of cleavage. The use of J(H)6 in the junctions (39%) was similar to that in the immunoglobulin genes of normal B cells and B-CLL, but considerably less than in FL. Only 2 of 36 samples contained a BCL-1/DJ(H) rearrangement, which was indicative of a previous DJ(H) rearrangement. Most importantly, 19% of the BCL-1/IgH junctions with inserts of > or =5 nucleotides contained error-prone copies (T-nucleotides) of 8-12 nucleotides originating from the surrounding BCL-1 or IgH regions, a lower rate than in FL. No correlation was found between the addition of T-nucleotides and the rate of somatic mutation in the immunoglobulin genes. We conclude that the t(11;14) and t(14;18) use the same basic mechanism of translocation including V(D)J-mediated recombination, double-strand staggered breaks, and template-dependent, error-prone DNA-synthesis. However, the distinct differences in the utilization of J(H) regions suggest that the t(11;14) occurs predominantly during an attempted primary D(H)-J(H) rearrangement in early B cells, whereas the t(14;18) mostly occurs during secondary rearrangement. This is in agreement with the pregerminal center B-cell origin of MCL.

Antiproliferative function of p27kip1 is frequently inhibited in highly malignant Burkitt's lymphoma cells.

Lack of detectable expression of p27kip1 cyclin dependent kinase inhibitor has previously been correlated with high degree of malignancy in human breast, colorectal, gastric and small cell lung carcinomas. Here we demonstrate that an inverse correlation between p27kip1 expression and tumour malignancy also exists in most types of human B cell lymphomas examined. A clear exception was Burkitt's lymphoma (BL), a highly malignant tumour which often expresses high levels of p27kip1. Analysis of p27kip1 derived from Burkitt's lymphoma cell lines expressing high levels of p27kip1, BL40 and BL41, in a cyclin E/cdk2 kinase inhibition assay demonstrated that p27kip1 is not permanently inactivated since heat treatment can restore the inhibitory activity of p27kip1. However, p27kip1 expressed in these two cell lines is largely sequestered in inactive complexes and we have no evidence that c-myc or Epstein-Barr virus are responsible for the sequestration of p27kip1 in these two cell lines although c-myc and EBV are two oncogenic agents often associated with Burkitt's lymphomas. Interestingly, we observed that high level p27kip1 expression often correlated with cyclin D3 overexpression both in vivo and in BL cell lines. The majority of p27kip1 in BL40 cells was complexed with cyclin D3 indicating that overexpressed cyclin D3 may at least be part of the sequestering activity for the inhibitory function of p27kip1. Furthermore, cyclinD3/cdk4 complex could sequester p27kip1 in a cyclin E/cdk2 kinase assay in vitro. Finally, we show that cyclin D3 transfected into an inducible p27kip1 cell line could overcome the G1 arrest mediated by p27kip1. These results argue that in addition to down-regulation of p27kip1 expression, some tumour cells can sequester and tolerate the antiproliferative function of p27kip1. They also suggest a novel role for the overexpression of D-type cyclins as one pathway allowing tumour cells to overcome the antiproliferative function of p27kip1.

The effect of a bi-annual professional application of APF foam on dental caries increment in primary teeth: 24-month clinical trial.

The purpose of this study was to evaluate the effect of a bi-annual professional application of acidulated phosphate fluoride (APF) foam on caries increment in the primary dentition over a two-year period in the People's Republic of China. In a double-blind, cluster-randomized, placebo-controlled trial, 392 children aged 3-4 years from 15 classes were randomly assigned to two groups on a school class basis. The experimental group (8 classes) received a bi-annual APF foam application, and the control group (7 classes) received the placebo. The mean increment of dmfs in the experimental group was 24.2% lower than that in the control group (p < 0.05). The significant caries reduction was observed on approximal surfaces in the experimental group compared with the control group (p < 0.01), but there were no differences on occlusal surfaces (p > 0.05). A bi-annual professional application of APF foam was effective in reducing the increment of dental caries in the primary teeth.

The prevalence of dental erosion in preschool children in China.

OBJECTIVE: To describe the prevalence of dental erosion and associated factors in preschool children in Guangxi and Hubei provinces of China. METHODS: Dental examinations were carried out on 1949 children aged 3-5 years. Measurement of erosion was confined to primary maxillary incisors. The erosion index used was based upon the 1993 UK National Survey of Children's Dental Health. The children's general information as well as social background and dietary habits were collected based on a structured questionnaire. RESULTS: A total of 112 children (5.7%) showed erosion on their maxillary incisors. Ninety-five (4.9%) was scored as being confined to enamel and 17 (0.9%) as erosion extending into dentine or pulp. There was a positive association between erosion and social class in terms of parental education. A significantly higher prevalence of erosion was observed in children whose parents had post-secondary education than those whose parents had secondary or lower level of education. There was also a correlation between the presence of dental erosion and intake of fruit drink from a feeding bottle or consumption of fruit drinks at bedtime. CONCLUSION: Erosion is not a serious problem for dental heath in Chinese preschool children. The prevalence of erosion is associated with social and dietary factors in this sample of children.

KLF2 mutation is the most frequent somatic change in splenic marginal zone lymphoma and identifies a subset with distinct genotype.

To characterise the genetics of splenic marginal zone lymphoma (SMZL), we performed whole exome sequencing of 16 cases and identified novel recurrent inactivating mutations in Kruppel-like factor 2 (KLF2), a gene whose deficiency was previously shown to cause splenic marginal zone hyperplasia in mice. KLF2 mutation was found in 40 (42%) of 96 SMZLs, but rarely in other B-cell lymphomas. The majority of KLF2 mutations were frameshift indels or nonsense changes, with missense mutations clustered in the C-terminal zinc finger domains. Functional assays showed that these mutations inactivated the ability of KLF2 to suppress NF-κB activation by TLR, BCR, BAFFR and TNFR signalling. Further extensive investigations revealed common and distinct genetic changes between SMZL with and without KLF2 mutation. IGHV1-2 rearrangement and 7q deletion were primarily seen in SMZL with KLF2 mutation, while MYD88 and TP53 mutations were nearly exclusively found in those without KLF2 mutation. NOTCH2, TRAF3, TNFAIP3 and CARD11 mutations were observed in SMZL both with and without KLF2 mutation. Taken together, KLF2 mutation is the most common genetic change in SMZL and identifies a subset with a distinct genotype characterised by multi-genetic changes. These different genetic changes may deregulate various signalling pathways and generate cooperative oncogenic properties, thereby contributing to lymphomagenesis.

The value of the polymerase chain reaction in the diagnosis of cutaneous T-cell infiltrates.

The distinction between reactive and neoplastic cutaneous T-cell infiltrates is difficult and requires good clinicopathologic correlation. Many cases manifest changes that are at the borderline between the two. The polymerase chain reaction (PCR) has been reported to detect monoclonality in 52-90% of cutaneous T-cell lymphomas and may be of use in the diagnosis of histologically borderline lesions. We have investigated the use of PCR in a series of borderline lesions including borderline biopsy samples from patients who subsequently developed cutaneous lymphoma. PCR amplification of T-cell receptor (TCR)-gamma chain gene was performed on formalin-fixed, paraffin-embedded tissue from 27 cases of clinically and histologically typical mycosis fungoides (MF), 22 borderline biopsy samples from 10 patients who subsequently developed MF (pre-MF), 32 clinically suspicious, histologically borderline lesions, and 31 cases of chronic dermatitis. Monoclonality was demonstrated in 16 of 27 (59%) cases of MF, 10 of 22 (50%) pre-MF biopsy samples (six of 10 patients), and six of 32 (19%) borderline biopsy samples. The same size monoclonal band was detected in pre-MF biopsy samples from six of seven patients in which a band was demonstrated in the diagnostic MF biopsy. Sequencing confirmed that the MF biopsy sample and the pre-MF biopsy sample contained the same clone. The 31 dermatitis cases gave rise to polyclonal PCR products. Monoclonality can be demonstrated using PCR in 59% of MF cases, which is comparable with other T-cell lymphomas and in up to 50% of borderline biopsy samples in patients who later develop lymphoma. Detection of T-cell monoclonality by PCR is strong evidence of an established or evolving cutaneous T-cell lymphoma.

The API2-MALT1 fusion exploits TNFR pathway-associated RIP1 ubiquitination to promote oncogenic NF-κB signaling.

The API2-MALT1 fusion oncoprotein is created by the recurrent t(11;18)(q21;q21) chromosomal translocation in mucosa-associated lymphoid tissue (MALT) lymphoma. We identified receptor interacting protein-1 (RIP1) as a novel API2-MALT1-associated protein, and demonstrate that RIP1 is required for API2-MALT1 to stimulate canonical nuclear factor kappa B (NF-κB). API2-MALT1 promotes ubiquitination of RIP1 at lysine (K) 377, which is necessary for full NF-κB activation. Furthermore, we found that TNF receptor-associated factor 2 (TRAF2) recruitment is required for API2-MALT1 to induce RIP1 ubiquitination, NF-κB activation and cellular transformation. Although both TRAF2 and RIP1 interact with the API2 moiety of API2-MALT1, this moiety alone is insufficient to induce RIP1 ubiquitination or activate NF-κB, indicating that API2-MALT1-dependent RIP1 ubiquitination represents a gain of function requiring the concerted actions of both the API2 and MALT1 moieties of the fusion. Intriguingly, constitutive RIP1 ubiquitination was recently demonstrated in several solid tumors, and now our study implicates RIP1 ubiquitination as a critical component of API2-MALT1-dependent lymphomagenesis.