bcl-2 protein is strongly expressed in post-transplant lymphoproliferative disorders

The aim of this study was to examine a series of Epstein-Barr virus (EBV)-driven post-transplant lymphoproliferative disorder (PTLDs), in order to ascertain the level of bcl-2 immunostaining; to explore the relationship between bcl-2 and p53 protein expression and to see if any correlation exists between bcl-2 and EBV-latent membrane protein 1 (LMP-1). Seventeen renal and 11 heart/heart-lung PTLD cases were stained with antibodies to EBV-LMP-1, bcl-2 and p53, using paraffin-embedded tissue. All cases of PTLD strong co-expressed bcl-2 and EBV-LMP. Positive staining was present in small lymphoid and larger immunoblastic cells. These two antibodies showed parallel staining intensity. p53 expression was noted in 13 of 17 renal PTLDs, but in ten of the positive cases only 5-10 per cent of cells were stained. Seven of the 11 heart/heart-lung cases showed 50-60 per cent of cells to be p53-positive; in the remaining for cases, 10-20 per cent of cells were positive. bcl-2 protein, as detected by immunohistochemistry, is markedly overexpressed in all case of PTLD. This study also demonstrates a strongly positive correlation between bcl-2 expression and EBV-LMP-1 detection in PTLD. An inverse pattern of p53 and bcl-2 immunoexpression is noted in PTLDs with "high grade' histology: these show marked expression of bcl-2, while p53 is downregulated. A Fisher's exact test yielded a P value of 0-12 when comparing p53-positive renal PTLDs with p53-positive heart/heart-lung PTLDs, indicating that any difference seen is not statistically significant. The postulated mechanism for the positive correlation between bcl-2 and EBV-LMP-1 is that EBV upregulates bcl-2, either directly or indirectly, thus promoting cell survival and ultimately successful viral replication.

The immunoexpression of bcl-2 and p53 in Kaposi's sarcoma

The aim of this study was to examine the immunohistochemical expression of p53 and bcl-2 in Kaposi's sarcoma and relate this with proliferation index (as measured by MIB-1 staining) and clinicopathological subtypes. Twenty formalin-fixed, paraffin-embedded cases of Kaposi's sarcoma were stained with commercially available antibodies to p53, bcl-2 and MIB-1, after pressure cooking antigen retrieval. All cases were strongly positive for bcl-2 with the majority containing more than 75% positive cells. In comparison, p53 expression was less striking. Eleven cases contained less than 24% (+1) of cells staining positively. Only two cases showed greater than 75% of positive cells, and both of these latter two lesions had metastasized. The MIB-1 staining in all cases of Kaposi's sarcoma was strongly positive, irrespective of clinicopathological type, in keeping with the highly proliferative nature of this lesion. Thus, we have demonstrated uniformly increased expression of bcl-2 protein in Kaposi's sarcoma irrespective of clinicopathological subtype and MIB-1 staining, while p53 expression is relatively less common, except in those cases which have metastasized. This may help identify those cases that will behave in a more aggressive manner. However, more cases need to be evaluated to verify this.

Thymidine phosphorylase expression in Kaposi sarcoma

AIMS

To examine the immunohistochemical distribution of thymidine phosphorylase (TP) in all clinicopathological subtypes of Kaposi sarcoma.

METHODS

Thirty two biopsy specimens of Kaposi sarcoma (29 patients) were studied. Six of these patients represented classic, six endemic, eight HIV associated, seven post-immunosuppression/transplant related, and two unclassified variants of Kaposi sarcoma. The average age was 49 years (range 22-83 years) and the male: female ratio 24:5. Four samples of angiosarcoma and one of spindle cell haemangio-endothelioma were stained in parallel. All specimens were fixed in formalin, embedded in paraffin wax and processed routinely. Immunohistochemistry was carried out using an antibody directed against CD31 (JC70) and the monoclonal antibody P-GF.44C against TP.

RESULTS

All biopsy specimens showed immunoexpression for TP. The spindle cell component stained more strongly than newly formed endothelium lined vessels and normal, resident vessels at a distance from the lesions.

CONCLUSIONS

The strong immunoexpression of TP suggests up-regulation of TP and a role for TP in angiogensis in Kaposi sarcoma. The mechanism for the up-regulation of TP remains unknown, but viral infections may trigger it. The differential staining of the various cell components of Kaposi sarcoma also suggest that TP either plays a role in the differentiation and maturation of Kaposi sarcoma or is a reflection of such changes.

An immunohistochemical study of TAL-1 protein expression in leukaemias and lymphomas with a novel monoclonal antibody, 2TL 242

Fifty formalin fixed, paraffin-embedded cases of T-acute lymphoblastic leukaemia (T-ALL) from 12 bone marrow trephines and 38 lymph nodes were stained with a new monoclonal antibody, 2TL 242, raised against recombinant TAL1 protein. The antibody recognizes TAL-1 polypeptides of molecular weight 39 and 41 kD (full length). In addition, a variety of other leukaemias and lymphomas were also stained with 2TL 242. Twenty-four of the 50 cases of T-ALL showed nuclear positivity, ranging from 10 to 90 per cent of leukaemic cells. A positive staining reaction was nuclear and stippled in pattern. Nuclear staining was not seen in any other type of leukaemia or lymphoma. Five cases of follicular lymphoma showed diffuse cytoplasmic staining of variable intensity. Although some background staining is obtained with this antibody, positive nuclear staining is easily distinguishable. This monoclonal antibody has a potential role in primary diagnosis and in the detection of minimal residual disease in T-ALL.

EBV latent membrane protein (LMP-1) and bcl-2 protein expression in Reed-Sternberg-like cells in post-transplant lymphoproliferative disorders

An inconsistent association exists between EBV-LMP-1 and bcl-2 protein expression in Reed-Sternberg cells seen in Hodgkin's disease. In fact, many studies have concluded that there is no correlation between EBV-LMP and bcl-2 expression in Hodgkin's disease. We undertook an analysis of post-transplant lymphoproliferative disorders to explore the relationship between EBV-LMP and bcl-2 in Reed-Sternberg-like cells found in this condition, given the strong association between this disorder and EBV. Reed-Sternberg-like cells were found histologically in 11 of 28 cases of renal, heart and heart-lung post-transplant lymphoproliferative disorders. Formalin-fixed, paraffinembedded sections were stained with monoclonal antibodies to EBV-LMP-1 and bcl-2 proteins. Reed-Sternberg-like cells in all 11 cases co-expressed EBV-LMP and bcl-2. A similar relationship was noted with large, mononuclear cells and occasional small lymphoid cells. The staining pattern seen with both antibodies was of similar intensity and both displayed cytoplasmic Golgi accentuation. In the setting of post-transplant lymphoproliferative disorders. Reed-Sternberg-like cells exhibit strong co-expression of EBV-LMP-1 and bcl-2 proteins, supporting a positive correlation between them. This is in contrast to the findings in Hodgkin's disease. The reason for this discrepancy may be due to the iatrogenic immunosuppression and resultant severe EBV infection, together with other cellular events.

EBNA expression in Reed-Sternberg like cells in post-transplant lymphoproliferative disorders

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C-erbB-2 oncoprotein expression in operable non-small cell lung cancer

Although c-erbB-2 oncoprotein immunohistochemical expression has been thoroughly studied in a variety of human tumors, its prognostic significance remains unclear. Moreover, differences in assessment criteria further complicate the evaluation of c-erbB-2 as a prognostic marker. In the present study we examined the expression of c-erbB-2 protein in 107 patients suffering from operable (T 1,2-N0, 1 staged) non-small cell lung cancer (30 adenocarcinomas and 69 squamous cell carcinomas) treated with surgery alone. A 3-7 year of follow up (median 45 months) was available for all patients. Paraffin embedded sections were stained with the NCL-CB11 monoclonal antibody using the immunoperoxidase technique. Analysis was based on cytoplasmic reactivity as membrane staining was impossible to assess against this background. Strong positive cytoplasmic staining was identified in 20/107 (19%) of cases, weak in 30/107 (20%) and negative in 57/107 (53%). Results were correlated with patient variables (age,sex) and tumor parameters (T,N-stage, grade, histology, Ki67 proliferation index, p53 and EGFR expression). C-erbB-2 expression was not related to any of these factors. Although c-erbB-2 defined a worse prognosis, univariate analysis of survival did not confirm any statistically significant difference between the c-erbB-2 staining groups (p=0.5). T,N-stage were the only statistically significant prognostic variables. Any contribution of c-erbB-2 to the development of tumour aggressive behaviour in non-small cell lung cancer requires assessment in the specific subgroups of patients.

Polycystin, the polycystic kidney disease 1 protein, is expressed by epithelial cells in fetal, adult, and polycystic kidney

Polycystic kidney disease 1 (PKD1) is the major locus of the common genetic disorder autosomal dominant polycystic kidney disease. We have studied PKD1 mRNA, with an RNase protection assay, and found widespread expression in adult tissue, with high levels in brain and moderate signal in kidney. Expression of the PKD1 protein, polycystin, was assessed in kidney using monoclonal antibodies to a recombinant protein containing the C terminus of the molecule. In fetal and adult kidney, staining is restricted to epithelial cells. Expression in the developing nephron is most prominent in mature tubules, with lesser staining in Bowman's capsule and the proximal ureteric bud. In the nephrogenic zone, detectable signal was observed in comma- and S-shaped bodies as well as the distal branches of the ureteric bud. By contrast, uninduced mesenchyme and glomerular tufts showed no staining. In later fetal (>20 weeks) and adult kidney, strong staining persists in cortical tubules with moderate staining detected in the loops of Henle and collecting ducts. These results suggest that polycystin's major role is in the maintenance of renal epithelial differentiation and organization from early fetal life. Interestingly, polycystin expression, monitored at the mRNA level and by immunohistochemistry, appears higher in cystic epithelia, indicating that the disease does not result from complete loss of the protein.

Immunohistochemistry in apparently normal bone marrow trephine specimens from patients with nodal follicular lymphoma

AIM

To establish the role of immunohistochemistry (using a limited panel of antibodies) in detecting minimal involvement by follicular lymphoma in routinely processed bone marrow trephine specimens, which show no obvious morphological (light microscopic) evidence of lymphoma; to determine whether bcl-2 immunostaining in bone marrow distinguishes between benign and malignant infiltrates in a patient with nodal follicular lymphoma.

METHODS

Twenty seven consecutively selected paraffin wax embedded, formalin fixed bone marrow trephine specimens were stained with the following antibodies: anti-bcl-2, anti-CD79a, anti-CD3, and kappa and lambda light chains, using the Streptavidin biotin complex technique.

RESULTS

Five of the 27 cases, which showed no evidence of involvement by follicular lymphoma on routine stains, showed monotypic B cells on immunohistochemistry. Two of the cases were diffuse, while the remaining three showed mini-aggregates around bony trabeculae. In all five cases the lymphomatous infiltrates were strongly bcl-2 positive. Reactive B lymphoid nodules did not show the same degree of bcl-2 positivity, and negative cells could be discerned within the reactive nodules.

CONCLUSIONS

There is merit in studying so-called negative bone marrows immunohistochemically in order to detect minimal involvement by follicular lymphoma. A limited panel of antibodies including anti-bcl-2, anti-CD79a and anti-CD3 is usually adequate to accomplish this. Strongly bcl-2 positive lymphoid aggregates in the bone marrow of patients with nodal follicular lymphoma are indicative of lymphoma.

SCL/Tal-1 expression in T-acute lymphoblastic leukemia: an immunohistochemical and genotypic study

A comparative study of the immunohistochemical (Stem cell leukemia/T-cell acute leukemia [SCL/TAL-1] protein expression) and genotypic (deletions in the SCL/tal-1 gene) findings in T-acute lymphoblastic leukemia (T-ALL) is presented. Formalin-fixed tissue from 50 cases of T-ALL were stained with a novel monoclonal antibody, 2TL 242, which recognizes SCL/TAL-1 protein. Twenty-four cases showed nuclear immunolabeling of leukemic cells. Nuclear positivity was not evident in any other type of leukemia or lymphoma tested with the antibody. Genotypic analysis of 25 cases of T-ALL showed a deletion involving the SCL/tal-1 gene in nine cases. These results suggest that protein expression is not dependent on derangement of the SCL/tal-1 gene, because immunohistochemical detection of the protein was noted in the presence and absence of a tal-d1 deletion.

TAL1 gene deletions and TAL1 protein expression in sporadic melanoma

Studies on cytogenetic abnormalities and cell lines have implicated chromosome 1p32 as being important in the pathogenesis of melanoma. Genetic linkage studies have also mapped a melanoma-susceptibility locus to chromosome 1p. The gene TAL1 is present on chromosome 1p32, and deletions within it are the commonest chromosomal abnormality in T-acute lymphoblastic leukaemia (T-ALL). A melanoma cell line harbouring a 1p32 deletion involving the TAL1 gene and the presence of TAL1 protein in developing mouse melanocytes led us to investigate whether TAL1 deletions and/or TAL1 protein expression occur in sporadic melanomas. DNA extracted from 32 fresh melanomas was amplified by standard polymerase chain reaction for the four common deletions of the TAL1 gene that occur in T-ALL. In addition, frozen and paraffin-embedded sections of these melanomas were stained with monoclonal antibodies that detect full-length and truncated TAL1 protein. The results of the study show that deletions of TAL1 do not occur in melanoma. Indeed, full and truncated TAL1 protein also could not be detected immunohistochemically in the paraffin-embedded and frozen sections of the melanomas. We conclude that the TAL1 gene and its protein are probably not directly involved in the oncogenesis of melanomas.

Primary Hodgkin's disease of the lung

Three cases of Hodgkin's disease presenting primarily in the lung are described. All 3 patients presented with respiratory symptoms and chest X-rays revealed discrete masses within the lung parenchyma. CT examination of the mediastinum did not reveal regional or generalized lymphadenopathy at the time of diagnosis in 2 of the cases. A diagnosis of Hodgkin's disease was made on open lung biopsies and despite aggressive chemotherapy, 2 patients died within 2 yrs. The histological and immunocytochemical features of these cases were typical of that expected in Hodgkin's disease. However, the stated indolent course of primary pulmonary Hodgkin's disease is not invariable. Those patients with bilateral interstitial disease and systemic symptoms have a poor prognosis. Furthermore, it is difficult to exclude definitely lymph node involvement (although not enlarged) at the time of diagnosis. Since several cases described in the literature have concurrent and/or subsequent nodal involvement, the entity of primary pulmonary Hodgkin's disease without lymph node involvement is exceedingly rare.

Immunohistochemical detection of p53 and Bcl-2 proteins in Hashimoto's thyroiditis and primary thyroid lymphomas

AIMS

To investigate whether immunohistochemical staining using p53 and/or bcl-2 distinguishes between florid Hashimoto's thyroiditis and low grade mucosa associated lymphoid tissue (MALT) lymphoma of the thyroid.

METHODS

Ten cases of Hashimoto's thyroiditis and eight of primary thyroid lymphoma were stained with monoclonal antibodies directed against p53 and bcl-2.

RESULTS

In Hashimoto's thyroiditis most small lymphoid cells in mantle zones, within the thyroid parenchyma and in lymphoepithelial lesions expressed bcl-2 protein. Very occasional centroblasts in reactive germinal centres were positive for p53, but all other lymphoid cells from cases of Hashimoto's disease were negative for p53. In diffuse, low grade lymphomas bcl-2 protein was uniformly expressed by most tumour cells. However, low grade lymphomas with a follicular pattern did not express bcl-2. The diffuse, low grade lymphomas were negative for p53, while occasional larger cells in the follicular subtype were positive. Both high grade lymphomas were bcl-2 negative but strongly p53 positive.

CONCLUSIONS

This study indicates that there is an inverse correlation between p53 and bcl-2 immunostaining in thyroid lymphomas (low grade lymphomas: bcl-2 positive, p53 negative; high grade lymphomas: bcl-2 negative, p53 positive). Furthermore, immunohistochemical staining for bcl-2 and p53 proteins does not distinguish florid Hashimoto's thyroiditis from diffuse, low grade thyroid lymphoma.

Subungual melanoma

Twenty (1.5%) of 1,350 patients with malignant melanoma treated during a 17-year period had their primary lesion in the nail bed. The thumb (5 patients) and big toe (7) were the most commonly involved digits. Mean delay before diagnosis was 1.4 years. Thirteen patients were black and 7 white. Eight patients (40%) were initially misdiagnosed as having traumatic, infective or benign lesions. Four patients presented with recurrent local disease after inappropriate nail excision or inadequate nail biopsy, while 2 patients had regional nodal spread and 2 had systemic metastases. Mean Breslow depth was 5.7 mm. The histogenetic subtypes were acral lentiginous melanoma (12 patients) and nodular melanoma (4 patients); 4 lesions were unclassifiable. All patients underwent amputation of the involved digit and 12 required node dissection (therapeutic in 11, prophylactic in 1). Five patients (25%) are alive (mean 52 months, range 29-99 months); 4 are disease-free and 1 has brain metastases. Overall median survival was 32 months with a 26% 5-year survival rate. Delayed diagnosis and advanced disease at presentation contributed to the poor prognosis in nail bed melanoma.

A single center randomized trial assessing use of a vascular hemostasis device vs. conventional manual compression following PTCA: what are the potential resource savings?

We undertook a randomized controlled trial comparing VasoSeal, a collagen vascular hemostasis device (VHD), with manual compression to assess its role and potential cost savings in the PTCA population. Of 460 patients, 359 were excluded due to clinical instability (30%), groin problems (18%), suboptimal PTCA result (15%), and other reasons (37%). The remaining 101 patients were randomized to either VHD (51) or manual compression (50). Hemostasis time, time to ambulation, duration of hospital stay, and nursing time and intensity were significantly reduced in the VHD group. There were no major groin complications in either treatment arm but there was a trend toward more minor groin complications in the VHD patients. The application of VasoSeal reduced resource use in this randomized study and may translate into significant cost reductions in the general coronary angioplasty population.

Paraganglioma-like (hyalinizing trabecular) adenoma of the thyroid revisited

The aim of the present study was to explore the association between paraganglioma-like adenomas of the thyroid (PLAT) and chronic lymphocytic thyroiditis (CLT) or Hashimoto's thyroiditis, and to discuss its possible relationship to papillary thyroid carcinoma. Six cases were analyzed by standard histopathological and immunohistochemical techniques. All 6 cases (all females) had clinical and/or histological evidence of CLT. Only one patient had 2 PLATs. The PLATs were devoid of inflammation and sharply demarcated from the surrounding CLT. There is cyto-morphological overlap with papillary thyroid carcinoma (nuclear grooves and pseudo-inclusions). We conclude that PLAT is associated with CLT more frequently than any other thyroid lesion, and feel that this is more than merely a chance association. PLAT shares several cytological features with papillary carcinoma and cases have been seen where they have occurred in the same thyroid. PLAT could therefore represent an unusual variant of papillary carcinoma.