Hongxiang Liu

Resistance of t(11;18) positive gastric mucosa-associated lymphoid tissue lymphoma to Helicobacter pylori eradication therapy

20-30% of gastric mucosa-associated lymphoid tissue (MALT) lymphoma associated with Helicobacter pylori do not regress after antibiotic therapy. Regression can be assessed only by extended follow-up. To assess whether t(11;18, q21;q21), which results in a chimeric transcript between the AP12 and MLT genes, predicts lymphoma resistance to antibiotic therapy, we screened for the fusion transcript with RT-PCR in ten responsive and 12 non-responsive gastric MALT lymphomas. The AP12-MLT transcript was detected in nine (75%) of 12 patients non-responsive to antibiotic therapy but not in responsive patients. Most H pylori-associated gastric MALT lymphomas that do not respond to antibiotic therapy are associated with t(11;18, q21;q21).

Long-Term Follow-Up of Gastric MALT Lymphoma After Helicobacter Pylori Eradication

PURPOSE Cure of infection induces remissions in most patients with early stage Helicobacter pylori- (Hp) positive gastric MALT (mucosa-associated lymphoid tissue) lymphoma (GML). We tracked the long-term stability of remissions in this prospective, multicenter trial. PATIENTS AND METHODS In 120 patients with stage I(1E) disease, we performed sequential endoscopic-bioptic follow-up after Hp eradication and polymerase chain reaction of the rearranged immunoglobulin heavy chain gene. The status of t(11;18) was assessed in 65 patients. RESULTS Median follow-up was 75 months (range, one to 116). Five-year survival was 90%. Eighty percent of patients (96 of 120) achieved complete histologic remission (CR). Eighty percent of CRs are in continuous complete histologic remission (CCR). Three percent of CR patients (three of 96) relapsed and were referred for alternative treatment. Seventeen percent of CR patients (16 of 96) showed histologic residual disease (RD) during follow-up; a watch-and-wait strategy was applied, and all entered into a second CR. After a median follow-up of 63 months, 14 of 52 analyzed patients reaching CR showed ongoing B-cell monoclonality. Fifteen percent of GMLs were t(11;18) positive. Both t(11;18) and ongoing monoclonality were associated with a significantly higher risk for no response or relapse (P =.004, P =.007), but also present in patients in CCR. Early gastric cancer was diagnosed in three cases during follow-up. CONCLUSION Cure of Hp infection results in CCR in most patients. Histologic RD, B-cell monoclonality, and t(11;18) were present in a considerable number of CR patients. A watch-and-wait strategy is justified when close follow-up is guaranteed.

Chlamydia psittaci is variably associated with ocular adnexal MALT lymphoma in different geographical regions

Infectious agents play a critical role in MALT lymphoma development. Studies from Italy showed Chlamydia psittaci infection in 87% of ocular adnexal MALT lymphomas and complete or partial regression of the lymphoma after C. psittaci eradication in four of nine cases. However, C. psittaci was not demonstrated in ocular adnexal MALT lymphomas from the USA. This study was thus designed to investigate further the role of C. psittaci, and other infectious agents commonly associated with chronic eye disease, in the development of ocular adnexal MALT lymphoma. The presence of C. psittaci, C. trachomatis, C. pneumoniae, herpes simplex virus 1 and 2 (HSV1, HSV2), and adenovirus 8 and 19 (ADV8, ADV19) was assessed separately by polymerase chain reaction in 142 ocular adnexal MALT lymphomas, 53 non‐marginal zone lymphomas, and 51 ocular adnexal biopsies without a lymphoproliferative disorder (LPD), from six geographical regions. C. psittaci was detected at similar low frequencies in non‐LPD and non‐marginal zone lymphoma groups from different geographical regions (0–14%). Overall, the prevalence of C. psittaci was significantly higher in MALT lymphomas (22%) than in non‐LPD (10%, p = 0.042) and non‐marginal zone lymphoma cases (9%, p = 0.033). However, the prevalence of C. psittaci infection in MALT lymphoma showed marked variation among the six geographical regions examined, being most frequent in Germany (47%), followed by the East Coast of the USA (35%) and the Netherlands (29%), but relatively low in Italy (13%), the UK (12%), and Southern China (11%). No significant differences in the detection of C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8, and ADV19 were found between lymphomas and controls from different geographical regions. In conclusion, our results show that C. psittaci, but not C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8 or ADV19, is associated with ocular adnexal MALT lymphoma and that this association is variable in different geographical areas. Copyright

EuroClonality/BIOMED-2 guidelines for interpretation and reporting of Ig/TCR clonality testing in suspected lymphoproliferations

PCR-based immunoglobulin (Ig)/T-cell receptor (TCR) clonality testing in suspected lymphoproliferations has largely been standardized and has consequently become technically feasible in a routine diagnostic setting. Standardization of the pre-analytical and post-analytical phases is now essential to prevent misinterpretation and incorrect conclusions derived from clonality data. As clonality testing is not a quantitative assay, but rather concerns recognition of molecular patterns, guidelines for reliable interpretation and reporting are mandatory. Here, the EuroClonality (BIOMED-2) consortium summarizes important pre- and post-analytical aspects of clonality testing, provides guidelines for interpretation of clonality testing results, and presents a uniform way to report the results of the Ig/TCR assays. Starting from an immunobiological concept, two levels to report Ig/TCR profiles are discerned: the technical description of individual (multiplex) PCR reactions and the overall molecular conclusion for B and T cells. Collectively, the EuroClonality (BIOMED-2) guidelines and consensus reporting system should help to improve the general performance level of clonality assessment and interpretation, which will directly impact on routine clinical management (standardized best-practice) in patients with suspected lymphoproliferations.

MALT lymphoma with t(14;18)(q32;q21)/IGH-MALT1 is characterized by strong cytoplasmic MALT1 and BCL10 expression

Mucosa‐associated lymphoid tissue (MALT) lymphoma is specifically associated with t(11;18)(q21;q21), t(1;14)(p22;q32) and t(14;18)(q32;q21). t(11;18)(q21;q21) fuses the N‐terminus of the API2 gene to the C‐terminus of the MALT1 gene and generates a functional API2‐MALT1 product. t(1;14)(p22;q32) and t(14;18)(q32;q21) bring the BCL10 and MALT1 genes respectively to the IGH locus and deregulate their expression. The oncogenic activity of the three chromosomal translocations is linked by the physiological role of BCL10 and MALT1 in antigen receptor‐mediated NFκB activation. In this study, MALT1 and BCL10 expression was examined in normal lymphoid tissues and 423 cases of MALT lymphoma from eight sites, and their expression was correlated with the above translocations, which were detected by molecular and molecular cytogenetic methods. In normal B‐cell follicles, both MALT1 and BCL10 were expressed predominantly in the cytoplasm, high in centroblasts, moderate in centrocytes and weak/negative in mantle zone B‐cells. In MALT lymphoma, MALT1 and BCL10 expression varied among cases with different chromosomal translocations. In 9/9 MALT lymphomas with t(14;18)(q32;q21), tumour cells showed strong homogeneous cytoplasmic expression of both MALT1 and BCL10. In 12/12 cases with evidence of t(1;14)(p22;q32) or variants, tumour cells expressed MALT1 weakly in the cytoplasm but BCL10 strongly in the nuclei. In all 67 MALT lymphomas with t(11;18)(q21;q21), tumour cells expressed weak cytoplasmic MALT1 and moderate nuclear BCL10. In MALT lymphomas without the above translocations, both MALT1 and BCL10, in general, were expressed weakly in the cytoplasm. Real‐time quantitative RT‐PCR showed a good correlation between MALT1 and BCL10 mRNA expression and underlining genetic changes, with t(14;18)(q32;q21)‐ and t(1;14)(p22;q32)‐positive cases displaying the highest MALT1 and BCL10 mRNA expression respectively. These results show that MALT1 expression pattern is identical to that of BCL10 in normal lymphoid tissues but varies in MALT lymphomas, with high cytoplasmic expression of both MALT1 and BCL10 characterizing those with t(14;18)(q32;q21). Copyright

A practical strategy for the routine use of BIOMED‐2 PCR assays for detection of B‐ and T‐cell clonality in diagnostic haematopathology

BIOMED‐2 polymerase chain reaction (PCR) assays for clonality analysis of immunoglobulin (IG) and T‐cell receptor (TCR) gene rearrangements were evaluated in routine haematopathological practice where paraffin‐embedded tissues constitute the majority of specimens. One hundred and twenty‐five fresh/frozen and 316 paraffin specimens were analysed for DNA quality and clonality. Seventy‐nine per cent of paraffin specimens yielded PCR products of over 300 bp. These specimens and all fresh/frozen specimens were analysed with the complete set of BIOMED‐2 reactions for IG (8 reactions) and/or TCR (6 reactions) gene rearrangements. The rate of detection of clonality was 96% in mature B‐cell neoplasms and 98% in mature T‐cell neoplasms and there were no significant differences in these rates between paraffin and fresh/frozen specimens. As the value of sole use of any individual BIOMED‐2 reaction in clonality detection was limited, we assessed combinations of reactions that gave the greatest sensitivity with fewest reactions and were applicable for both fresh/frozen and paraffin specimens. For IG gene rearrangements, three reactions combining one targeting the IG heavy chain framework‐2 region and two targeting the IG kappa locus achieved a 91% detection rate. For TCR gene rearrangements, the two TCR gamma reactions gave a 94% detection rate. We therefore recommend this strategy as the first‐line assays for routine B‐ and T‐cell clonality analysis in diagnostic haematopathology.

Angioimmunoblastic T-cell lymphoma: histological progression associates with EBV and HHV6B viral load

The clinical and histological presentations of angioimmunoblastic T‐cell lymphoma (AITL) often mimic an infectious process. Epstein–Barr virus (EBV) and human herpes virus (HHV6) are known to be associated with AITL, but whether these viral infections play a role in its pathogenesis is unclear. It also remains to be investigated whether there might be other viruses associated with AITL. We first screened 26 well‐characterised cases of AITL for herpesvirus by polymerase chain reaction (PCR) with universal primers and found evidence of only EBV and HHV6B infection. Subsequent PCR using virus‐specific primers demonstrated EBV and HHV6B infection in 40/49 biopsies (36/42 cases) and 21/49 biopsies (19/42 cases) of AITL respectively with both viral infections found in 17/49 specimens (15/42 cases). Importantly, simultaneous infection with both viruses was found only in specimens showing histological pattern II (n = 2) or III (n = 15). Interestingly, among specimens containing both viruses, there was a tendency towards an inverse correlation between the EBV and HHV6B viral load as shown by quantitative PCR. In specimens positive only for EBV, the viral load was significantly higher in specimens with histological pattern III than those with pattern II. High EBV load was also significantly associated with B‐cell monoclonality. Double EBV encoded small RNA (EBER) in situ hybridisation and immunohistochemistry indicated that EBV‐infected B cells had a late postgerminal centre immunophenotype. Our results demonstrate an association between EBV and HHV6B infection and the histological progression of AITL, suggesting that these viruses may play a role in the pathogenesis of this lymphoma.

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.

Clinical impact of genetic aberrations in gastric MALT lymphoma: a comprehensive analysis using interphase fluorescence in situ hybridisation

Background and aims: There is a need for genetic biomarkers to guide prognosis and management of gastric mucosa-associated lymphoid tissue (MALT) lymphomas. We assessed the incidence and clinical significance of the MALT lymphoma-associated genetic abnormalities t(11;18)/API2-MALT1, t(1;14)/BCL10-IGH, t(14;18)/IGH-MALT1, t(3;14)/FOXP1-IGH, and extra copies of MALT1 and FOXP1 in gastric MALT lymphomas from Japan. Methods: The presence of translocations and copy number changes involving MALT1, IGH and FOXP1 were assessed in 90 cases of gastric MALT lymphoma using interphase fluorescence in situ hybridisation (FISH). In cases carrying a MALT1 translocation, FISH for API2-MALT1 was performed, whereas in those carrying an IGH translocation, FISH was performed for BCL10, BCL6, BCL2, c-MYC and/or CCND1. Results: t(11;18)/API2-MALT1 was detected in 18 of 87 (21%) cases and was significantly associated with Helicobacter pylori-negativity, resistance to H pylori eradication and Bcl10 nuclear expression. Four of 68 (6%) cases carried a translocation involving IGH and FOXP1 (n = 1), BCL2 (n = 1) or an unknown partner (n = 2). Neither t(1;14)/BCL10-IGH nor t(14;18)/IGH-MALT1 was detected. Extra copies of MALT1 and FOXP1 were detected in 18 of 71 (25%) cases and 10 of 59 (17%) cases, respectively. The presence of extra copies of MALT1 was significantly associated with progression or relapse of lymphoma, and was an independent adverse prognostic factor for event-free survival as determined by multivariate analysis. Conclusions: t(11;18)/API2-MALT1 is frequent, whereas IGH-involved translocations are rare in gastric MALT lymphoma in Japan. The presence of extra copies of MALT1, often suggestive of partial or complete trisomy 18, is a frequent genetic aberration in gastric MALT lymphoma, which appears to predict adverse clinical behaviour.

Strong BCL10 nuclear expression identifies gastric MALT lymphomas that do not respond to H pylori eradication.

Approximately 75% of gastric mucosa associated lymphoid tissue (MALT) lymphomas can be cured by Helicobacter pylori eradication.1 It would be very useful to identify, at the time of diagnosis, the 25% of cases of gastric MALT lymphoma that will not respond to H pylori eradication. In general, lymphomas at stage IIE or above do not respond to H pylori eradication.2–4 However, the prognostic value of staging in stage IE cases is very limited, although tumours that involve the muscularis propria or serosa (stage IE2) show a higher failure rate than those restricted to the mucosa and submucosa (stage IE1).2–4 Paradoxically, the majority of gastric MALT lymphomas at diagnosis are at stage IE but 20% of these cases will not respond to H pylori eradication. In a previous study, we have examined the value of t(11;18)(q21;q21) in prediction of the response …