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.

Gastric and intestinal diffuse large B-cell lymphomas are clinically and immunophenotypically different. An immunohistochemical and clinical study.

AIMS: To determine the immunophenotype of gastric and intestinal diffuse large B-cell lymphomas and investigate the clinical significance of patterns of antigen expression. METHODS AND RESULTS: Immunohistochemistry was performed for detection of CD10, Bcl-6, Bcl-2, MUM1 and p53 in paraffin-embedded tissue from 29 patients with primary diffuse large B-cell lymphoma of the stomach and intestine. Statistical analysis was performed using chi(2) and Fisher's exact tests. Survival data were analysed by the Kaplan-Meier method and compared using a log rank test. Thirteen of the 29 cases were of germinal centre phenotype (CD10+ or CD10-, Bcl-6+ and MUM1-). Sixteen were of activated B-cell phenotype (all CD10- and either Bcl-6-, or Bcl-6+ and MUM1+). Sixteen cases showed Bcl-2 expression. There was a statistically significant difference (P < 0.05) in immunophenotype of the neoplastic cells relating to tumour site. Of 15 gastric lymphomas, 11 were of activated B-cell phenotype and 9/14 intestinal tumours were of germinal centre phenotype. No significant survival difference was found between groups with regard to expression of any of the antigens investigated. CONCLUSIONS: Primary gastric and intestinal large cell lymphomas appear to show different patterns of antigen expression. This suggests that these tumours arise by different mechanisms and/or from different causes. Gastric diffuse large B-cell lymphomas are usually of activated B-cell phenotype that may reflect a relationship with low-grade gastric lymphomas of marginal zone type. Intestinal diffuse large B-cell lymphomas usually show a germinal centre phenotype, suggesting an origin from germinal centre B cells. In this study the tumour immunophenotype was not associated with any difference in survival.

Does providing social services with information and advice on immunisation status of "looked after children" improve uptake?

We prospectively assessed whether providing social services with information on the immunisation status for a cohort of looked after children in the care of an urban unitary authority in England improved uptake rates. The provision of such information did not improve immunisation coverage in these children.

Evaluation of fine-needle aspiration cytology for renal masses.

OBJECTIVE: To evaluate the accuracy and use of fine-needle aspiration (FNA) cytology for the diagnosis of renal masses because with the improved quality and increasing use of ultrasonography and computed tomography (CT), asymptomatic renal masses, particularly small (< 5 cm) tumours, are being discovered more frequently. PATIENTS AND METHODS: Between 1995 and 1997, 49 patients (mean age 67.5 years, range 42-88, 34 men and 14 women) underwent FNA of a solid or complex cystic mass under radiological guidance. All masses were further evaluated and staged by CT. Solid masses were divided according to size (< 5 cm and >/= 5 cm). Patients were followed up to the determination of a final diagnosis on tissue histology, after nephrectomy where possible. RESULTS: Thirty-six patients had histologically confirmed carcinoma at nephrectomy, and nine had presumed carcinoma (four unfit for surgery, five with advanced malignancy). The remaining four patients had benign diagnoses. FNA produced insufficient sample in eight cases (16%). The sensitivity was 89% for large (>/= 5 cm) solid masses, 64% for small (< 5 cm) solid masses and 50% for complex cysts. CONCLUSION: FNA does not contribute to the diagnosis of malignancy in large (> 5 cm) masses, as good radiological imaging is nearly always diagnostic. For smaller (< 5 cm) masses and complex cysts, FNA can occasionally confirm malignancy, but lack of diagnostic yield and low sensitivity means that FNA is unreliable as a diagnostic tool and will rarely help in the routine management of these patients.

Aggressive NK cell lymphoma preceded by a ten year history of neutropenia associated with large granular lymphocyte lymphocytosis.

We report a case of aggressive natural killer (NK) cell lymphoma in an 82 year old man who first presented 10 years earlier with neutropenia in association with a large granular lymphocyte (LGL) lymphocytosis. The diagnosis of NK cell lymphoma was made on the basis of morphological and immunological characteristics (CD3-CD56+) found on skin biopsy of one of multiple skin nodules which subsequently developed in association with splenomegaly, thrombocytopenia and continuing neutropenia. In addition there was BM infiltration and a cytogenetic abnormality [add(6)(p25)] was detected. Combination chemotherapy led to an initial clinical response but a relapse occurred shortly afterwards and the patient died 8 months later from infection whilst neutropenic following re-introduction of chemotherapy. Previously reported cases of aggressive NK cell lymphoma have shown a young male predominance with a rapidly progressive clinical course and without evidence of a preceding chronic phase of LGL lymphocytosis and neutropenia.

Molecular analysis of T-cell clonality in ulcerative jejunitis and enteropathy-associated T-cell lymphoma.

Ulcerative jejunitis (UJ) and enteropathy-associated T-cell lymphoma (EATL) are closely related conditions both associated with celiac disease. Benign-appearing inflammatory ulcers are seen in both, which has led to the suggestion that UJ is a manifestation of EATL. The aim of this study was to investigate this relationship using the polymerase chain reaction (PCR) to detect T-cell gene rearrangement. PCR amplification of the T-cell receptor gamma-chain gene was performed on DNA extracted from lymphoma, associated inflammatory ulcers, and intervening mucosa in six EATL cases and from ulcers and intervening mucosa of seven cases of UJ. In two of these cases, DNA from a subsequent lymphoma was also studied. The PCR products from the tumor and an ulcer from one EATL case, two ulcers from one case of UJ, and one ulcer and subsequent cutaneous lymphoma from one UJ case were sequenced. Twenty-five ulcers from twelve cases of Crohn's disease, twenty sections of normal bowel, and nine celiac biopsies were included as controls. A monoclonal T-cell population defined by a dominant band equal in size to that amplified from the lymphoma was identified in at least one ulcer from four informative EATL cases and from intervening mucosa in three. Monoclonality was demonstrated in at least one, and up to thirteen, ulcers from all seven cases of UJ, in intervening mucosa in five, and in the two subsequent lymphomas. Sequencing showed the same clone was present in the tumor and the ulcer in the EATL case, in two of three ulcers from the UJ case, and in an ulcer and subsequent cutaneous lymphoma in one UJ case. All Crohn's disease ulcers and all sections of normal bowel were polyclonal. One of nine celiac biopsies showed a dominant band. In conclusion, we have shown that T-cell monoclonality is a feature of the ulcers in both UJ and EATL and that the same clone is present in EATL and its associated inflammatory ulcers and in UJ and subsequently developing lymphoma.

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.

Immunoglobulin light chain staining in paraffin-embedded tissue using a heat mediated epitope retrieval method.

We have compared light chain immunohistochemistry in reactive lymphoid tissue and a series of paraffin-embedded B-cell lymphomas using standard trypsin digestion with a heat mediated epitope retrieval method. Fifty-seven B-cell lymphomas (18 high grade, 29 low grade and 10 cases of nodular lymphocyte predominance Hodgkin's disease), two reactive lymph nodes and eight tonsils fixed for known times between 12 h and 2 years were studied. Paraffin-embedded tissue was stained with polyclonal anti-kappa and anti-lambda antibodies. For each antibody staining was performed on two sections, one treated with trypsin digestion and one with microwave heating. Sections were scored from 0 to + + + with 0 representing poor staining and + + + excellent staining. A score of ++ was considered satisfactory. Light chain restriction was recorded if present. Satisfactory staining was obtained in 34/59 cases using trypsin digestion and 56/59 cases using heat retrieval. Light chain restriction was demonstrated in 32/57 (56%) B-cell lymphomas using trypsin digestion and 52/57 (91%) using heat retrieval. Satisfactory staining was obtained in tonsils fixed for up to 48 h using trypsin digestion and up to 2 years using heat retrieval. We have shown that for light chain immunostaining a heat mediated epitope retrieval method produces more consistent and satisfactory results and is effective over a greater range of fixation times than traditional trypsin digestion.

HLA antigen expression in enteropathy associated T cell lymphoma.

AIMS: To investigate the occurrence of abnormal patterns of HLA-ABC and HLA-DR expression in enteropathy associated T cell lymphoma and to relate such abnormalities to the Epstein Barr virus (EBV) status of the tumours. METHODS: Eleven enteropathy associated T cell lymphomas were immunostained with HC10 (HLA-ABC heavy chain) and TAL 1B5 (HLA-DR alpha chain) monoclonal antibodies and polyclonal anti-beta 2 microglobulin (beta 2m, the HLA-ABC light chain) antibodies. In situ hybridisation for EBV using EBER probes was performed on all cases. RESULTS: Tumour cells of two of 11 patients were EBER positive. One of these showed partial, and the other, complete loss of beta 2m. HLA-DR expression was undetectable in both patients. Of the remaining nine EBER negative tumours, two were HLA-ABC heavy chain negative or showed only occasional positive cells and five of nine showed partial or complete loss of the HLA-ABC light chain, beta 2m. Seven of the nine cases were either negative for HLA-DR or showed weak expression in a proportion of tumour cells. CONCLUSIONS: These data show that low or absent HLA-ABC and HLA-DR antigen expression occurs commonly in enteropathy associated T cell lymphoma. These abnormal patterns of HLA expression may be associated with escape from immune attack which, in a minority of patients, could be directed against EBV antigens.

Detection of Helicobacter pylori in gastric biopsy and resection specimens.

AIMS: To compare the sensitivity of detecting Helicobacter pylori in gastric biopsy and resection specimens using tinctorial and silver impregnation stains, immunohistochemistry and the polymerase chain reaction (PCR). METHODS: Formalin fixed, paraffin wax embedded tissue from 33 gastric biopsy specimens (26 showing chronic gastritis and seven showing low grade mucosa associated lymphoid tissue (MALT) lymphoma) together with blocks of uninvolved mucosa from gastrectomy specimens for MALT lymphoma (five cases) were studied. Consecutive sections were stained using haematoxylin and eosin, Giemsa, the Warthin-Starry silver stain, and a polyclonal antibody directed against H pylori using an immunoperoxidase technique following heat induced antigen retrieval. PCR analysis of DNA extracted from a further section was carried out using primers which amplified a 411 base pair fragment of the urease A gene. RESULTS: H pylori was detected in 14 (37%) sections stained with haematoxylin and eosin, 21 (55%) with Giemsa, 23 (61%) with Warthin-Starry, and 25 (66%) stained with the antibody. Seventeen (45%) cases were positive on PCR. Immunohistochemistry was positive in all cases in which H pylori was detected by other methods. CONCLUSION: Immunohistochemistry using an immunoperoxidase technique following heat induced antigen retrieval for detecting H pylori in gastric biopsy and resection specimens is highly sensitive and easy to use.

Cadherins in reactive lymph nodes and lymphomas: high expression in anaplastic large cell lymphomas.

Using a polyclonal pan-cadherin antibody and a monoclonal E-cadherin antibody (HECD-1) we have investigated cadherin expression in lymphomas and reactive lymph nodes. Routinely processed tissue from nine reactive lymph nodes and 48 lymphomas (six T-cell, six high-grade B-cell, 15 low-grade B-cell, 13 anaplastic large cell and eight Hodgkin's disease) were immunostained. The reactive cases showed pan-cadherin membrane associated staining of endothelium and epithelioid granulomas. No staining of lymphoid cells was seen. Pan-cadherin immunostaining was present in three of six T-cell lymphomas, two of six high-grade B-cell lymphomas, 12 of 13 anaplastic large cell lymphomas and three of eight cases of Hodgkin's disease. No staining of low-grade B-cell lymphomas was identified with the pan-cadherin antibody. E-cadherin was not detected in any of the lymphomas that showed pan-cadherin expression. The frequent and strongest cadherin expression in anaplastic large cell is noteworthy. The tumour cells of this lymphoma subtype are characterized by copious cytoplasma and a cohesive appearance, features which impart a superficial resemblance to carcinoma cells. Since cadherin molecules are known to have major morpho-regulatory functions our data suggests that the expression of cadherin molecules by anaplastic large cell lymphomas may play an important role in determining their characteristic epithelioid phenotype.

A comparative study of the value of immunohistochemistry and the polymerase chain reaction in the diagnosis of follicular lymphoma.

We have compared the value of immunohistochemical and polymerase chain reaction (PCR) techniques in distinguishing follicular lymphoma from follicular hyperplasia in formalin-fixed paraffin-embedded tissues of 41 follicular lymphomas, 15 reactive lymph nodes and 5 reactive tonsils. Immunohistochemistry demonstrated bcl-2 protein in the follicle centre cells of 97% of follicular lymphomas whereas monoclonal immunoglobulin light chain was detected in 83% of cases. Assessing the lowest proliferating follicle of each case by MIB-1 immunostaining, proliferation fractions in the lymphomas varied from 0.5% to 59% (mean 15.6%). Over 80% of lymphomas had proliferation fractions of less than 25%. PCR detected gene rearrangement either at the bcl-2 locus, or at the IgH locus, or at both loci in 32%, 44% and 61% of lymphomas, respectively. The follicle centre cells of the reactive lymph nodes and tonsils were all bcl-2 protein negative and polytypic for kappa and lambda light chains. Proliferation fractions of the lowest proliferating follicle in each reactive case ranged from 30.5% to 86.8% (mean 64.9%). Rearrangements of the bcl-2 or IgH loci were not detected in any reactive case. This study demonstrates that bcl-2 and light chain immunostaining are the most consistently helpful aids to diagnosing follicular lymphoma. A low proliferation fraction also indicates lymphoma but a high proliferation fraction does not exclude the diagnosis. Immunostaining with a combination of anti bcl-2 and MIB 1 antibodies is a sensitive and specific method for identifying follicular lymphoma, is technically simple to perform and easy to interpret. In occasional cases, where immunostaining gives equivocal results, PCR analysis can confirm lymphoma, but a negative result does not exclude the diagnosis.

Follicular Hodgkin's disease.

We describe four cases of Hodgkin's disease that presented histologically as purely follicular lesions. The Reed-Sternberg (RS) cells were of classic and lacunar type and had the phenotype of usual Hodgkin's disease (CD30 and CD15 positive) but also expressed B-cell antigens (CD20 and CD79a). In each case the follicles consisted principally of mantle-zone B cells, which enclosed the RS cells; the follicle centres were atrophic, usually eccentrically placed, and did not contain RS cells. Fifteen cases of typical nodular sclerosing Hodgkin's disease were reviewed in parallel. B-cell antigen expression by RS cells was found in 10 cases (66%), and RS cells were present in follicular mantles in 10 cases. These findings suggest that some RS cells may be derived from B cells in the follicular mantle.