Correlation between cytopathological results and in situ hybridisation on needle aspiration biopsies of suspected African Burkitt's lymphomas

Epstein-Barr virus infection of infants: implications of early age of infection on viral control and risk for Burkitt lymphoma

Since its first description by Denis Burkitt, endemic Burkitt's lymphoma (BL), the most common childhood cancer in sub-Saharan Africa, has led scientists to search for clues to the origins of this malignancy. The discovery of Epstein-Barr virus (EBV) in BL cells over 50 years ago led to extensive sero-epidemiology studies and revealed that rather than being a virus restricted to areas where BL is endemic, EBV is ubiquitous in the world's population with an estimated greater than 90% of adults worldwide infected. A second pathogen, Plasmodium falciparum (P. falciparum) malaria is also linked to BL. In this review, we will discuss recent studies that indicate a role for P. falciparum malaria in dysregulating EBV infection, and increasing the risk for BL in children living where P. falciparum malaria transmission is high.

Modulation of innate immunity system by Epstein-Barr virus-encoded non-coding RNA and oncogenesis

Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) are polyA-, non-coding RNAs that are expressed abundantly in all forms of cells latently infected with EBV. EBERs (EBER1 and EBER2) contribute to the clonal proliferation of EBV-negative Burkitt's lymphoma (BL) cells in soft agar, tumorigenicity in SCID mice, up-regulation of the bcl-2 oncoprotein, resistance to apoptosis, and maintenance of malignant phenotypes in BL cells. EBERs induce the expression of interleukin (IL)-10 in BL cells, insulin-like growth factor 1 (IGF-I) in gastric and nasopharyngeal carcinoma cells, IL-9 in T cells, and IL-6 in lymphoblastoid cell lines. Additionally, each of these cytokines acts as an autocrine growth factor. In BL cells, EBERs bind the double-stranded RNA-activated protein kinase PKR, inhibit its phosphorylation, and thereby prevent IFN-alpha-mediated apoptosis. In epithelial cells, EBERs confer resistance to Fas-mediated apoptosis by blocking PKR activity. EBERs form complexes with PKR, ribosomal protein L22, lupus erythematosis-associated antigen (La), and retinoic acid-inducible gene I (RIG-I). In BL cells, EBERs activate RIG-I signaling and induce the expression of type-I IFNs and interferon stimulated genes (ISGs) through the activation of RIG-I substrates, nuclear factor-kappa B (NF-kappaB), and IFN regulatory factor 3 (IRF-3), and anti-inflamatory cytokine IL-10 through IRF-3 but not NF-kappaB signaling. EBERs also play critical roles in the growth transformation of B lymphocytes. Although EBER1 and EBER2 exhibit similarities in their primary (54%) and secondary structures, recent findings have shown that recombinant EBVs carrying only the EBER2 gene play a greater role in the growth transformation of B lymphocytes than EBVs carrying only the EBER1 gene. Thus, EBERs play multiple roles in various cell types, and we present a model that highlights the functions of EBERs in EBV-mediated oncogenesis in BL cells.

Pilot study of sodium phenylbutyrate as adjuvant in cyclophosphamide-resistant endemic Burkitt's lymphoma

Burkitt's lymphoma (BL) accounts for the majority of childhood malignancies seen in sub-Saharan Africa. In Malawi, cyclophosphamide (CPM), the mainstay of treatment for endemic BL, is effective in around 50% of cases. Evidence exists in support of an association between activation of replication of Epstein-Barr virus (EBV) in the tumour and response to this chemotheraupeutic agent. Phenylbutyrate (PB), approved for treatment of inborn errors of the urea cycle with minimal toxicity in children, induces EBV replication and cell lysis in BL-derived cell cultures. It has also shown some success as adjuvant in treatment of chronic leukaemia and lymphoma. We tested in African BL patients with CPM-resistant tumours, and thus unlikely to survive, the hypothesis that PB can reverse this resistance. A study of five patients showed PB before CPM to induce shrinkage of CPM-resistant tumours in two of them. Findings suggested that for this effect PB pre-treatment should be given for a week before CPM treatment. A larger study is indicated.

Long term survival of children with Burkitt lymphoma in Malawi after cyclophosphamide monotherapy

BACKGROUND

Between 1991 and 1997, limited funding at times restricted available treatment for children with Burkitt lymphoma (BL) to cyclophosphamide (CPM) monotherapy at Lilongwe Central Hospital, Malawi. Our objective was to assess long-term survival in Malawian children with Burkitt lymphoma (BL) who had received one or more treatments with intravenous CPM at 40 mg/kg/dose at 14-day intervals.

PROCEDURE AND RESULTS

The study population consisted of 92 children in whom BL had been confirmed on fine needle aspirates (FNA), a home address had been documented on discharge from hospital, and the treatment records could be verified. Only the clinical site(s) of disease had been recorded. The M:F ratio was 1.4 and median age 8 years. A clinical officer on motorcycle attempted to locate the given addresses and interview parents or other sources. In 19 patients, the address was incorrect. Of 73 evaluable patients, 40 children are alive at a mean follow-up time of 59 (range: 29-104) months. The survival rate was 63.5% in 52 children with BL of the head only, and 33.3% in 21 children with primary disease involving the abdomen or other sites. Survivors had received a median number of 6 (range: 1-12), non-survivors 4 (range: 1-12), and untracable children 3 (range: 1-11) courses of CPM.

CONCLUSIONS

We confirmed that CPM could cure children with facial and abdominal BL. The unavoidable bias in the selection of patients and the variable amount of CPM given, precludes accurate survival estimates. A prospective study with proper staging, assessment of FNA, marrow and cerebrospinal fluid with modern techniques, a standard treatment protocol, and adequate follow-up will better define the current therapeutic value of CPM monotherapy. CPM can be purchased at about 3 US dollars per 500 mg.

Promiscuous expression of Epstein-Barr virus genes in Burkitt's lymphoma from the central African country Malawi

Primary BL in Malawian children has a very high frequency association, approaching 100%, with the human herpesvirus EBV. A detailed study carried out on viral gene expression in these tumours, using both fresh material and methanol-fixed FNAs, showed, contrary to prediction, that most belong to a variant "class II" latency category, with lytic cycle-related genes also expressed. That is, in addition to EBNA1 expression, membrane proteins (LMP1/2A), immediate early (BZLF1) and early (IR2 and IR4) genes, a putative viral oncogene (BARF1), CST (BART) antisense transcripts and the viral bcl-2 homologue are expressed in a high proportion of the BLs. Most, but not all, express the small viral (EBER) RNAs. Two other significant observations were made: (i) in addition to expression of cellular cytokine (IL-10) transcripts in all tumours investigated, the normally silent viral IL-10 homologue was expressed in some tumours; (ii) whereas EBNA1 expression from its restricted Qp promoter was generally observed, the nonrestricted Cp/Wp promoter was also active in some tumours. Viral gene expression in the Malawian [endemic (e)] BLs appears to be more promiscuous than predicted from other studies, but expression accords with the cytopathologic picture of eBLs as a rapidly proliferating cell population accompanied by considerable necrosis, and a clinically diverse disease. A small-scale study of relapse Malawian BLs revealed a different picture of viral association, more akin to systemic BL than eBL, where EBV appears to be absent or present only at very low levels. The significance of these findings is considered.

Epstein-Barr virus (EBV) and human disease: facts, opinions and problems

The human herpesvirus, Epstein-Barr virus (EBV), has classically been associated with two pathologies with frequencies approaching 100%. One of these, Burkitt's lymphoma (BL), is of B-cell origin and the other, nasopharyngeal carcinoma (NPC), is a tumour of poorly differentiated epithelial cells. More recently, EBV had been identified with frequencies from a few percent to 100% (in one case) with a variety of other malignancies. These include Hodgkin's disease (HD; where in the west, the frequency of association is about 50%), sino-nasal T-cell lymphomas, lymphoepitheliomas, some sarcomas and breast cancers, other cancers from the head and neck, and lymphomas arising in patients with immune dysfunctions. Since EBV is ubiquitous, with the vast majority of the world's population having met and seroconverted to the virus, the diversity of tumours with which it has now been associated represents a substantial health burden. In a recent IARC monograph, EBV was classified as a group 1 carcinogen. Here, the data on BL and NPC, as they relate to geographical restrictions, viral strain variation, co-factors in disease, and genetic components are reexamined. We raise the question whether in their origins, these tumours genuinely reflect distinct and independent events, as deemed at present, or may represent a response by different cell types to common extracellular factors. For example, a situation in Kenya apparently existed in the past, where both BL and NPC were observed in ethnic Africans with roughly equal frequencies; more recently, in Kenya, EBV has been identified in nearly 100% of the tumours in children with HD. We also consider tumours where the viral association is reportedly of low frequency, and offer explanations for these data, including the possibility of loss of the viral genome once malignancy has been initiated. If this phenomenon occurs as a frequent secondary event, EBV could be an even greater health risk than presently believed.

Role of fine-needle aspiration in the clinical management of solid organ transplant recipients: a review

BACKGROUND

We evaluated the clinical course of the solid-organ transplant population at our institutions to determine the role of fine-needle aspiration (FNA) in the clinical management of this subgroup of patients.

METHODS

1196 allograft recipients (522 liver, 288 cardiac, 250 renal, 131 lung, 5 heart and lung) were reviewed. A total of 62 (5.2%) (32 liver, 23 heart, 6 lung, and 1 renal) transplant patients underwent an FNA procedure. Thirty-seven males and 25 females were included, ranging in age from 18 to 71 years (mean 50 years).

RESULTS

Of the 62 fine-needle aspirates, 29 (47%) were neoplastic. The most common malignancies aspirated were malignant solid tumors (15 cases)-including 8 epithelial malignancies, 5 hepatocellular carcinomas, and 2 mesenchymal neoplasms-followed by posttransplant lymphoproliferative disorders (14 cases). Thirteen (21%) aspirates were inflammatory. The remaining 20 (32%) cases were benign aspirates from various sites (9 liver, 3 breast, 2 thyroid, 2 soft tissue, 2 lung, and 2 vertebral body). Surgical and/or autopsy material was available in 34 cases (55%). There was agreement between the tissue diagnosis and FNA material in 33 cases (97%). One case (3%) was a false negative. No false-positive cases were recorded.

CONCLUSIONS

This study showed that over 50% of the aspirates were benign, justifying a conservative approach in the clinical management of these patients. Histologic correlation was available in 54% of the cases with an overall specificity of 100% and a sensitivity of 97%. We conclude that FNA is a highly sensitive and specific technique in the evaluation of lesions occurring in posttransplant patients. Cancer (Cancer Cytopathol)

Expression of Epstein-Barr virus lytically related genes in African Burkitt's lymphoma: correlation with patient response to therapy

A study on the Epstein-Barr virus (EBV)-associated malignancy (endemic) Burkitt's lymphoma (BL) was initiated on fine-needle-aspiration biopsies from 46 proven BL cases in Malawi. Gene expression that might correlate with patient serology (where high levels of antibodies to lytically related genes are commonly observed) was explored. In two-thirds of the cases, we identified the EBV BZLF1 replication activator intermediate early protein ZEBRA in varying quantities and to varying extents in cells by immuno-cytochemistry. The early lytic-cycle gene transcript BHLF1 was assessed positively by solid-phase hybridisation in over half of the same tumours. Evidence of transcription of these genes was confirmed on a smaller number of surgically removed fresh biopsies by RT-PCR. We asked whether our findings, which are generally counter to the established notion that EBV gene expression in BLs is restricted to the latent function, EBNA1, might offer some explanation for the differential responses to chemotherapy observed among African patients. Where the duration of follow-up was sufficient to assign the cases (37 in number) to one of 3 categories, namely, complete, partial or no response, a significant correlation between expression of the viral function ZEBRA and a positive patient response to treatment was found. Lack of this was associated with poor prognosis. Clinical data and EBV gene expression results support the postulate of subgroups of African BLs, the intermediate early antigen providing a marker of potential use in patient management.

Role of fine-needle aspiration in clinical management of transplant patients

Fine-needle aspiration (FNA) of superficial and deep seated lesions has been used with high sensitivity and specificity in the diagnosis of neoplastic and non-neoplastic entities. However, studies of FNA in post-transplant patients are virtually absent. Six hundred and seventy-four allograft recipients (cardiac 288, renal 250, lung 131 and heart-lung 5) were reviewed. A total of 30 (25 heart, 4 lungs and 1 renal transplant) patients underwent an FNA procedure. There were 26 males and 4 females. Ages ranged from 18-63 yr (mean 48 yr). The most common entity aspirated was post-transplant lymphoproliferative disorder (PTLD) in 12 cases, followed by inflammatory lesions in 10 cases, malignant epithelial neoplasms in 3 cases, and 1 case each of malignant mesenchymal tumor, pulmonary infarction, hamartoma of liver, fatty changes of liver, and a benign vascular lesion. Surgical or autopsy tissue was available in 19 cases (63.3%). There was an agreement between tissue diagnosis and FNA material in 18 cases (94.7%). One (5.2%) false negative case was recorded. This was a liver aspirate showing benign liver elements, which a surgical biopsy proved to be a bile duct hamartoma. No false positive cases were recorded. FNA is a highly sensitive and specific diagnostic tool in the management of post-transplant patients.

Initial management of advanced Burkitt lymphoma in children: is there still a place for surgery?

This retrospective study compared the overall survival, the event-free survival, and the timing of chemotherapy in patients with advanced Burkitt lymphoma with and without laparotomy. Thirty-five patients with advanced abdominal Burkitt lymphoma treated at least partially at the Centre Léon Bérard between 1981 and 1992 were included in this study. The diagnosis was obtained by laparotomy (LAP group) in 21 patients (17 stage III, 4 stage IV) and by other methods (non-LAP group) in 14 patients (5 stage III, 9 stage IV). The overall survival (71 and 93%) and the event-free survival (66 and 79%) were similar in the LAP and non-LAP groups, and the relapse rate was five (three local) in the LAP group compared with three (none local) in the non-LAP group. The local complication rate (9 of 21 versus 2 of 14) and the toxic death rate (2 of 21 versus 1 of 14) were slightly higher in the LAP group. Laparotomy also caused delays in therapy and increased the overall hospital stay. The mean interval from diagnosis to the start of the fourth course of chemotherapy was 57 days compared with 48 days and the average hospital stay was 44.4 days compared with 39 days for the LAP and non-LAP groups, respectively. Because advanced Burkitt lymphoma can be diagnosed by fine-needle aspiration, and chemotherapy cures more than 80% of the patients, there is no need for initial surgery, apart from acute emergencies. Furthermore, laparotomy delay chemotherapy and might reduce the survival rate.

Posttransplant lymphoproliferative disorders: a fine-needle aspiration biopsy study

Fine-needle aspiration biopsy (FNAB) has been used with high sensitivity and specificity in the diagnosis of both Hodgkin's and non-Hodgkin's lymphoma. However, studies of FNAB of posttransplant lymphoproliferative disorders (PTLDs) are rare. The clinical course of 593 allograft recipients (cardiac, 288; renal, 250; lung, 50; and heart/lung, 5) was reviewed. Twenty-six patients developed PTLD with an overall incidence of 4.4%. Of these patients, 12 underwent FNAB. Their age ranged from 33-67 yr (mean, 55 yr). The interval between transplantation and FNAB ranged between 2-14 mo (average, 8.4 mo). The lungs were the most common site aspirated (7 cases), followed by lymph nodes (3 cases) and other extranodal sites (2 cases, liver and paraspinal mass). The cytologic features of these aspirates could be classified into two categories: a polymorphous smear composed of a spectrum of mature and immature lymphocytes with scattered plasma cells and histiocytes; and a monotonous population of large lymphoid cells consistent with malignant lymphoma, large-cell type. Surgical biopsies were available in 10 (83.3%) cases and confirmed the FNAB diagnosis. In summary, FNAB appears to be a highly sensitive and specific diagnostic tool in patients with PTLD.