Bcl-6 and c-Myc are rarely co-expressed in adult diffuse large B-cell lymphoma

Bcl-6 is expressed in germinal centre derived B-cell non-Hodgkin lymphomas including diffuse large B-cell lymphoma (DLBCL) and is likely to play a major role in driving proliferation of a subset of DLBCLs, especially those of germinal centre B-cell subtype, but the role of c-Myc, which is important for proliferation in various lineages is not known. We used the highly standardised staining conditions of a tissue microarray to characterise co-expression of c-Myc and Bcl-6 in DLBCL. We carried out immunohistochemistry of 73 arrayed cases. The majority (62/73) did not express c-Myc, but 11 cases (15%) showed nuclear staining. 5/53 (9%) of Bcl-6 expressing cases co-expressed c-Myc, whereas a much higher proportion, 6/20 (30%), of Bcl-6 negative cases were positive for c-Myc. Overall survival of c-Myc expressing cases was the same as those that had absent expression. There was no significant correlation between c-Myc expression and DLBCL subtype (germinal centre or non-germinal centre subtypes).

Absence of cyclin-D2 and Bcl-2 expression within the germinal centre type of diffuse large B-cell lymphoma identifies a very good prognostic subgroup of patients

AIMS

To validate and improve the existing algorithm (proposed by Hans et al.) to classify diffuse large B-cell lymphoma (DLBCL).

METHODS AND RESULTS

Tissue microarrays constructed from 81 patients with DLBCL were studied by immunohistochemistry for expression of CD10, Bcl-6, MUM1, Bcl-2, cyclin-D2, FOXP1 and PKC-gamma proteins. Cases were classified as either germinal centre B-like (GCB) or non-GC according to Hans et al. An alternative classification was also employed, in which cases positive for either CD10 or Bcl-6 were considered as a GC subgroup and cases negative for both CD10 and Bcl-6 were considered as a non-GC subgroup. GC was further subdivided into favourable GC (negative for both Bcl-2 and cyclin-D2) and unfavourable GC (positive for either Bcl-2 or cyclin-D2). The 5-year event-free survival (EFS) amongst patients classified as favourable GC versus 'others' was 49.5% and 7.3%, respectively (log rank P < 0.0001). Similarly, the 5-year overall survival (OS) amongst patients classified as favourable GC versus 'others' was 58.6% and 13.7%, respectively (log rank P = 0.0001). The difference in survival was independent of the international prognostic index.

CONCLUSIONS

In this group of patients the risk stratification based on the new algorithm was better than that proposed by Hans et al.

Bone marrow trephine combined with immunohistochemistry is superior to bone marrow aspirate in follow-up of myeloma patients

AIMS

Multiple myeloma (MM) guidelines in the UK do not advocate performing bone marrow trephine biopsy (BMTB) during follow-up. In a recent study, it was found that the plasma cell per cent (PC%) in BMTB performed at the time of autologous stem cell transplant strongly correlated with survival. The current study addresses whether BMTB is superior to bone marrow aspiration (BMA) in documenting presence of disease and its volume at follow-up.

METHODS

The study involved 106 samples. A conventional 500-cell differential count was performed on the BMAs to document the PC%. The PC% on BMTBs had been estimated on CD138 immunostain. Furthermore, BMTBs had also been immunostained for CD56, cyclin D1 and light chains.

RESULTS

The mean (2SEM) PC% values in BMAs and BMTBs were 13.1 (2.6)% and 31.8 (5.8)% respectively. Based on BMA, BMTB and serum/urine paraprotein or light chain estimation, on 92 occasions (89%) there was detectable disease. The positive predictive value of both BMA and BMTB was 100%, and the negative predictive values for BMTB and BMA were 57% and 22% respectively. Among 98 secretory MM cases, the BMTB-PC% showed significant correlation with paraprotein levels, whereas BMA-PC% did not.

CONCLUSIONS

It is strongly recommended that BMTB is performed and adequately investigated with immunohistochemistry during follow-up of MM.

In vivo evidence for apoptosis in the bone marrow in systemic lupus erythematosus

An increase in leucocyte apoptosis and impaired clearance of apoptotic cells has been observed in patients with systemic lupus erythematosus (SLE). Apoptotic cells are likely to be a key source of autoantigens in SLE as they express many of the nuclear autoantigens (in surface blebs and apoptotic bodies) that are relevant to this disease. The clearance of apoptotic cells is usually a rapid process, such that few cells are usually seen in the extracellular environment in vivo. We report a case in which multiple apoptotic bodies were observed in the bone marrow of a patient with SLE that was complicated by an immune-mediated pancytopenia. We have subsequently examined the frequency of apoptotic cells, identified morphologically, and by caspase-3 staining in bone-marrow trephine samples taken from patients with SLE over a 10-year period of follow-up. A high proportion of bone marrows contained apoptotic debris. The novel demonstration of apoptotic bodies in vivo in patients with SLE is unusual and supports the notion that the marrow may be a target organ in the disease. Their abundance is also consistent with the hypothesis that normal clearance mechanisms are defective and/or overwhelmed in SLE.

Optimal processing of bone marrow trephine biopsy: the Hammersmith Protocol

Specimens of bone marrow trephine biopsy (BMT) are transported and fixed in acetic acid-zinc-formalin fixative, decalcified in 10% formic acid-5% formaldehyde and processed with other specimens to paraffin-wax embedding. Sections, 1-microm-thick, are cut by experienced histotechnologists and used for haematoxylin and eosin, Giemsa, reticulin silver and other histological stains. Further, all immunohistochemical procedures used in the laboratory, including double immunostaining, can be used on these sections with no or minimal modifications. About 10,000 BMT specimens have been analysed using this procedure since 1997 and diseases involving the bone marrow have been classified successfully. More recently, standardised polymerase chain reaction-based analysis and mRNA in situ hybridisation studies have been conducted. Excellent morphology with good antigen, DNA and RNA preservation is offered by the Hammersmith Protocol.

The expression of minichromosome maintenance protein-2 in normal and abnormal megakaryocytes and comparison with the proliferative marker Ki-67

The minichromosome maintenance (Mcm) and Cdc6 proteins are important regulators of eucaryotic DNA replication. In most normal tissues, a similar proportion of cells express Mcm-2 and Ki-67. The present study showed that in both normal and abnormal states, the proportion of megakaryocytes expressing Mcm-2 is roughly seven times as many as those that express Ki-67. This is likely to be related to the process of endomitosis and endoreduplication. We also demonstrated that a significantly lower proportion of megakaryocytes in myelodysplastic syndrome express Mcm-2. These findings provide new insights into megakaryocyte biology.

Changes in endometrial blood vessels in the endometrium of women with hormone replacement therapy-related irregular bleeding

BACKGROUND

Irregular bleeding affects up to 60% of hormone replacement therapy (HRT) users. The mechanism of this bleeding is not understood. Reduced endometrial microvascular integrity appears to underlie breakthrough bleeding in pre-menopausal women and the aim of this study was to establish whether similar changes are seen in HRT users and hence to elucidate a possible mechanism of irregular bleeding.

METHODS

Endometrium from 34 HRT users with amenorrhoea, irregular bleeding or regular bleeding was assessed for endometrial endothelial cell density (anti-CD34), number of blood vessels per mm(2), vascular basal lamina components (laminin, collagen IV and heparan sulphate proteoglycan) and in 32 subjects and 23 controls for perivascular smooth muscle alpha (SMA). Findings were compared with a control population of 29 post-menopausal women not using HRT, other sex steroids or tamoxifen and with no vaginal bleeding. Staining intensity was assessed in a blinded fashion in all immunohistochemical studies.

RESULTS

Four significant differences in endometrial blood vessels were observed between HRT users and controls: (i) a significantly lower density of endometrial endothelial cells (EC staining for CD34) per mm(2) was present in HRT users compared with controls (P < 0.001); (ii) endothelial cells (EC) were predominantly organized within blood vessels (83%) in controls but in HRT users EC were dispersed in the tissues with only 29% in organized vessels (P <0.001); (iii) supportive perivascular cell SMA was significantly reduced in 23 post-menopausal HRT users compared with 23 post-menopausal controls (n = 29, P = 0.013) and (iv) an atrophic or inactive histological pattern of endometrium was more frequently seen in the controls (P < 0.001).

CONCLUSIONS

These findings support the hypothesis that exposure to HRT profoundly alters endometrial blood vessels, reducing structural integrity thereby predisposing to irregular bleeding in HRT users.