Improved Natural Killer cell activity and retained anti-tumor CD8(+) T cell responses contribute to the induction of a pathological complete response in HER2-positive breast cancer patients undergoing neoadjuvant chemotherapy.

BACKGROUND: Locally advanced HER2-overexpressing breast cancer (BC) patients achieve a high rate of pathological complete responses (pCR) after neoadjuvant chemotherapy (NC). The apparently unaltered immune proficiency of these patients together with the immune-modulating activities of NC drugs suggest a potential contribution of host immunity in mediating clinical responses. We thus performed an extensive immunomonitoring in locally advanced BC patients undergoing NC to identify immunological correlates of pCR induction. METHODS: The immune profile of 40 HER2-positive and 38 HER2-negative BC patients was characterized at diagnosis and throughout NC (Paclitaxel and Trastuzumab, or Docetaxel and Epirubicin, respectively). The percentages of circulating immune cell subsets including T and B lymphocytes, Natural Killer (NK) cells, regulatory T cells, T helper 17 lymphocytes, were quantified by multiparametric flow cytometry. NK cells functional activity was evaluated through the analysis of NF-kB nuclear translocation by Multispectral flow cytometry, and with the in vitro monitoring of Trastuzumab-mediated antibody-dependent cell cytotoxicity (ADCC). CD8(+) T cell responses against six different tumor-associated antigens (TAA) were characterized by IFN-γ ELISPOT and IFN-γ/IL-2 DualSpot assays. RESULTS: After NC, HER2-positive patients showed a significant increase in the number of NK cells and regulatory T cells irrespective of the pathological response, whereas patients undergoing a pCR disclosed higher percentages of T helper 17 cells. Notably, a significant increase in the number of activated NK cells was observed only in HER2-positive patients achieving a pCR. Characterization of anti-tumor T cell responses highlighted sustained levels of CD8(+) T cells specific for survivin and mammaglobin-A throughout NC in patients undergoing a pCR in both arms. Moreover, HER2-positive patients achieving a pCR were characterized by a multi-epitopic and polyfunctional anti-tumor T cell response, markedly reduced in case of partial response. CONCLUSIONS: These results indicate that maintenance of functional T cell responses against selected antigens and improvement of NK cell proficiency during NC are probably critical requirements for pCR induction, especially in HER2-positive BC patients. Trail registration: TRIAL REGISTRATION NUMBER: NCT02307227, registered on ClinicalTrials.gov ( http://www.clinicaltrials.gov , November 26, 2014).

Thymidine phosphorylase expression is associated with time to progression in patients receiving low-dose, docetaxel-modulated capecitabine for metastatic breast cancer.

BACKGROUND: Preclinical data have indicated a synergistic interaction between docetaxel and capecitabine by means of taxane-induced up-regulation of thymidine phosphorylase (TP). On the basis of such premises, we conducted a phase II trial to determine the activity and tolerability of weekly docetaxel plus capecitabine in patients with metastatic breast cancer (MBC). Furthermore, we explored the relationship between TP tumor expression and benefit from this regimen. PATIENTS AND METHODS: Patients received docetaxel 36 mg/m(2) i.v. on days 1, 8, and 15 and capecitabine orally 625 mg/m(2) b.i.d. from days 8 to 21. Cycles were repeated every 4 weeks. In the correlative study, we evaluated the TP expression by immunohistochemistry and the TP messenger RNA expression by real-time RT-PCR in the primary tumor. RESULTS: Forty-seven women were enrolled. In the intention-to-treat analysis, objective responses were achieved in 24 patients (51%). Fourteen additional patients (30%) had stable disease. The median time to progression (TTP) was 6 months (range 1-44 months). Median survival was 17 months (range 1-48 months). Overall, the treatment was well tolerated. The most common clinical adverse events (all grades) were alopecia (55%), nail changes (53%), fatigue/asthenia (51%), nausea/vomiting (51%), neutropenia (49%), and neuropathy (49%). A significantly higher TTP was observed in patients with TP-positive tumors (log-rank test, P = 0.009). Interestingly, a subgroup analysis confirmed this TTP benefit in patients with TP-positive tumors obtaining a tumor response (log-rank test, P = 0.03), whereas the statistical significance was lost in nonresponders (log-rank test, P = 0.3). CONCLUSIONS: This study indicates that a regimen with low doses of capecitabine plus weekly docetaxel is active against MBC. The correlative analysis provides preliminary evidence that TP expression may be a predictive marker for therapeutic benefit.

Radiotherapy-induced miR-223 prevents relapse of breast cancer by targeting the EGF pathway.

In breast cancer (BC) patients, local recurrences often arise in proximity of the surgical scar, suggesting that response to surgery may have a causative role. Radiotherapy (RT) after lumpectomy significantly reduces the risk of recurrence. We investigated the direct effects of surgery and of RT delivered intraoperatively (IORT), by collecting irradiated and non-irradiated breast tissues from BC patients, after tumor removal. These breast tissue specimens have been profiled for their microRNA (miR) expression, in search of differentially expressed miR among patients treated or not with IORT. Our results demonstrate that IORT elicits effects that go beyond the direct killing of residual tumor cells. IORT altered the wound response, inducing the expression of miR-223 in the peri-tumoral breast tissue. miR-223 downregulated the local expression of epidermal growth factor (EGF), leading to decreased activation of EGF receptor (EGFR) on target cells and, eventually, dampening a positive EGF-EGFR autocrine/paracrine stimulation loop induced by the post-surgical wound-healing response. Accordingly, both RT-induced miR-223 and peri-operative inhibition of EGFR efficiently prevented BC cell growth and reduced recurrence formation in mouse models of BC. Our study uncovers unknown effects of RT delivered on a wounded tissue and prompts to the use of anti-EGFR treatments, in a peri-operative treatment schedule, aimed to timely treat BC patients and restrain recurrence formation.

Characterization of a novel HHV-8-positive cell line reveals implications for the pathogenesis and cell cycle control of primary effusion lymphoma.

Primary effusion lymphoma (PEL) represents a peculiar type of B cell lymphoma which associates with HHV-8 infection and preferentially grows in liquid phase in the serous body cavities. In this report, we provide the detailed characterization of a newly established PEL cell line, termed CRO-AP/6. The cell line was obtained from the pleural effusion of a HIV-positive patient with PEL. Its derivation from the tumor clone was established by immunogenotypic analysis. Detailed phenotypic investigations defined that CRO-AP/6 reflects pre-terminally differentiated B cells expressing the CD138/syndecan-1 antigen. Karyotypic studies of CRO-AP/6 identified several chromosomal abnormalities, whereas genotypic studies ruled out the involvement of molecular lesions associated with other types of B cell lymphoma. Both CRO-AP/6 and the parental tumor sample harbored infection by HHV-8. Conversely, EBV infection was present in the parental tumor sample although not in CROAP/6, indicating that CRO-AP/6 originated from the selection of an EBV-negative tumor subclone. The pattern of viral (HHV-8 v-cyclin) and cellular (p27Kip1) regulators of cell cycle expressed by CRO-AP/6, together with the results of growth fraction analysis, point to abrogation of the physiological inverse relationship between proliferation and p27Kip1 expression. Also, both CRO-AP/6 and the parental tumor sample display biallelic inactivation of the DNA repair enzyme gene O6-methylguanine-DNA methyltransferase (MGMT) by promoter methylation. Overall, the CRO-AP/6 cell line may help understand cell cycle control of PEL cells, may clarify the relative contribution of HHV-8 and EBV to the disease growth and development and may facilitate the identification of recurrent cytogenetic abnormalities highlighting putative novel cancer related loci relevant to PEL.

Increased chemosensitivity to doxorubicin of intrinsically multidrug-resistant human colon carcinoma cells by prolonged exposure to verapamil.

Resistance modifying agents (RMA) such as verapamil (VER) have proved effective in reversing multidrug resistance (MDR) in many in vitro experimental models, but clinical results with RMA have been disappointing. To clarify this apparent discrepancy we have evaluated the cytotoxic effects of doxorubicin (DOX) plus VER in four human colon carcinoma (HCOC) cell lines (LoVo, DLD-1, SW948, SW1116). These lines were selected on the basis of their levels of mdr1 mRNA being similar to those expressed by HCC obtained from non-drug-treated patients. In all cell lines the sensitising effect of VER on DOX cytotoxicity was schedule-dependent and maximal potentiation of DOX cytotoxicity was obtained by exposure to VER for a time > or = the cells' population doubling time.

Immunohistochemical evaluation of multiple biological markers in ductal carcinoma in situ of the breast.

In order to obtain prognostic clinicopathological information, 49 cases of pure ductal carcinoma in situ of the breast (DCIS), were evaluated for the immunohistochemical expression of potential predictor markers including c-erbB-2 oncogene product, p53 protein, oestrogen (ER) and progesterone (PR) receptors, oestrogen-regulated proteins pS2 and cathepsin-D (cath-D), CD44 protein and 67-kDa laminin receptor (MLuC5). Immunohistochemical findings were compared with conventional pathological parameters, clinical findings, and the clinical outcome of the patients. When markers were matched to each other, statistical analyses provided a significant positive correlation between c-erbB-2 overexpression and p53 positivity (P < 0.01) and between ER and PR (P < 0.01), ER, PR and pS2 (P < 0.01), pS2 and MLuC5 (P < 0.05). Significant negative correlations between c-erbB-2 overexpression and ER (P < 0.05), PR (P < 0.01) and pS2 (P < 0.01) positivity was also observed. Data on the relationship between marker status and pathological findings revealed a significant positive trend between c-erbB-2, p53, and increased grade values (P < 0.05) and opposite results with PR receptor expression (P < 0.01). c-erbB-2 overexpression was further significantly associated with comedotype carcinoma (P < 0.05) and distribution of disease in confluent neoplastic ducts (P < 0.01). Although no statistically significant correlation among biological markers expression, clinical findings and outcome was demonstrated, overall this study indicates that tumour cells from a subset of DCIS, which includes comedotype carcinoma, express significantly unfavourable prognostic factors.

Primary Hodgkin's disease of the vagina.

We describe a patient with primary Hodgkin's disease (HD) of the vagina presenting with stage IEB. To our knowledge, this is the first case reported so far. Based on morphological and immunophenotypic features, the HD was classified as nodular sclerosis subtype, "syncytial" variant. The patient, a 64-year old woman, received chemotherapy followed by radiation therapy. She is still disease-free 14 months after diagnosis.

Primary effusion lymphoma cell lines harbouring human herpesvirus type-8.

Primary effusion lymphoma (PEL) is a novel lymphoma entity consistently infected by HHV-8 that occurs predominantly in immunodeficient patients and is characterized by liquid growth in the serous body cavities. In order to facilitate the understanding of PEL pathogenesis and histogenesis, we have established three PEL cell lines termed CRO-AP/2, CRO-AP/3 and CRO-AP/5. All cell lines have been derived from HIV positive homosexual men affected by PEL with (in the case of CRO-AP/2 and CRO-AP/5) or without (in the case of CRO-AP/3) a previous history of Kaposi's sarcoma. The cell lines are representative of both virologic variants of PEL, i.e. HHV-8+ EBV+ PEL (CRO-AP/2 and CRO-AP/5) and HHV-8+ EBV- PEL (CRO-AP/3). Morphologic and phenotypic features of CRO-AP/2, CRO-AP/3 and CRO-AP/5 are typical of PEL, and include morphology bridging immunoblastic and anaplastic features as well as an indeterminate (non B- non T-cell) phenotype. The B-cell nature of the cell lines is documented by the presence of rearranged immunoglobulin genes. The detailed analysis of the molecular and phenotypic features of CRO-AP/2, CRO-AP/3 and CRO-AP/5 has allowed the identification of recurrent chromosomal abnormalities of PEL and has contributed to the definition of PEL as a lymphoma of post-germinal center, pre-terminally differentiated B-cells.

BCL-6 in aids-related lymphomas: pathogenetic and histogenetic implications.

AIDS-related non-Hodgkin's lymphomas (AIDS-NHL) are classified into Burkitt's lymphoma, diffuse large cell lymphoma (DLCL), and body cavity based lymphoma. The molecular pathogenesis of AIDS-NHL is complex and involves the genetic alteration of several cancer related genes, including the BCL-6 proto-oncogene. BCL-6 encodes a zinc finger transcription factor which is selectively expressed by germinal center (GC) B-cells, but not by pre-GC or post-GC B-cells. Genetic alterations of BCL-6 occur frequently among B-cell NHL and comprise gross rearrangements as well as small mutations of the 5' noncoding region of the gene. Gross rearrangements of BCL-6 among AIDS-NHL cluster with 20% AIDS-DLCL. Conversely, mutations of the 5' noncoding region of BCL-6 occur at sustained frequency throughout the clinico-pathologic spectrum of AIDS-NHL and represent the most common genetic alteration presently detectable in these lymphomas. The frequency of BCL-6 mutations, as well as their location in the proximity of the BCL-6 regulatory regions, suggest that they may play a pathogenetic role in AIDS-related lymphomagenesis. Beside their pathogenetic implications, the occurrence of BCL-6 mutations among AIDS-NHL bears histogenetic relevance because BCL-6 mutations are regarded as a marker of B-cell transition through the GC. Thus, it is conceivable that a large fraction of AIDS-NHL is histogenetically related to GC or post-GC B-cells. This notion is further confirmed by the observation that AIDS-NHL frequently express the BCL-6 protein, which stains selectively GC B-cells throughout B-cell differentiation.

Temporomandibular joint metastasis from rectal carcinoma: CT findings before and after radiotherapy. A case report.

Metastatic disease to the masticator space and to the jaws is a rare event. About a dozen cases are reported in the current literature. We describe the imaging findings of a rectal adenocarcinoma metastatic to the temporomandibular joint before and after radiotherapy.

[Cytogenetic analysis in the definition and classification of non-Hodgkin's lymphomas]. / Contributo dell' analisi citogenetica alla definizione e classificazione dei linfomi non-Hodgkin.

Cytogenetic analysis of Non-Hodgkin's Lymphomas (NHL) taken together with immunophenotypic and genotypic studies, may contribute to better define their morphologic classification. In this review the main cytogenetic data have been summarized, looking at a histopathologic NHL categorization that is related to a modern multiparametric approach. The correlation of non random chromosome abnormalities with NHL categories will augment information about their pathogenesis and tumor progression.

Doxorubicin, vincristine, and actinomycin-D, but not teniposide, require long-lasting uninterrupted verapamil pressure to overcome drug resistance in multidrug-resistant cells.

The cytotoxic efficacy of doxorubicin (DOX), vincristine (VCR), actinomycin-D (ACT-D), and teniposide (VM-26) toward the LoVo and SW948 multidrug-resistant (MDR) cell sublines was significantly enhanced by the concomitant presence of verapamil (VER) during pharmacological treatment (1-h exposure) without, however, achieving a complete reversion of the MDR phenotype. Long-lasting VER in the culture medium, at the end of the combined drug+VER treatment, conferred to DOX, VCR, and ACT-D cytotoxic efficacy roughly similar to that exerted on the drug-sensitive parent cell lines. On the contrary, no enhancement of VM-26 cytotoxic efficacy was derived from continuous VER treatment. Enhancement of DOX, VCR, and ACT-D cytotoxic efficacy requires that VER be present in an uninterrupted manner in the culture medium since brief interruptions (15 to 60 min) in the VER pressure completely counteract any effect. These findings offer new insight into the modalities of pharmacological treatment that MDR cells require to obtain a complete reversion of cellular resistance to the various drug families included in the MDR spectrum.

[The pathology spectrum of AIDS-related non-Hodgkin's lymphoma]. / Lo spettro patologico dei linfomi non-Hodgkin AIDS-correlati.

Patients with acquired immunodeficiency syndrome (AIDS) are at increased risk of developing non Hodgkin's lymphomas (NHL). Current estimates indicate that 5-10% of HIV-infected individuals develop AIDS-related NHL (AIDS-NHL). AIDS-NHL share several clinical features, including frequent extranodal presentation, aggressive clinical course and poor outcome. However, AIDS-NHL are a heterogeneous group of malignancies. They traditionally included systemic and primary brain lymphomas, but nowadays their updated clinicopathologic spectrum also comprises two novel entities, namely primary effusion lymphoma and plasmablastic lymphoma of the oral cavity. In the last few years, several studies have shown that the pathologic heterogeneity of AIDS-NHL correlates with the heterogeneity of the molecular lesions associated with these lymphomas. However, despite their pathologic and molecular heterogeneity, AIDS-NHL have a common B-cell origin, although the precise stage of B-cell differentiation reflected by the different tumor types has not been clarified yet.

P53 overexpression in human soft tissue sarcomas: relation to biological aggressiveness.

BACKGROUND: The tumor suppressor protein p53 is overexpressed in a large fraction of human tumors. It has been supposed that p53 abnormalities may be an early event that contributes to the neoplastic transformation; alternatively, p53 overexpression might be related to progression toward more aggressive tumor phenotypes. The aim of the present work was to better clarify the role of p53 overexpression in human soft tissue sarcomas (IISTS). DESIGN: p53 immunohistochemistry analysis using the Pab 1801 was performed in frozen samples of HSTS obtained from 61 patients. Tumors were classified according to the WHO criteria, histologic grading was based on the criteria of Enzinger and Weiss, and DNA ploidy and S-phase determination was performed by flow cytometrical analysis. RESULTS: Of all the HSTS we analyzed, p53 protein over-expression occurred more frequently in G3 grade tumors (p < 0.01), HSTS of III A-B stage (p = 0.02) and in aneuploid tumors (p < 0.01). CONCLUSIONS: The association of p53 overexpression with parameters of biological aggressiveness suggests an involvement of p53 in the neoplastic progression of HSTS. This assumption is supported by the findings that in tumors with a mixed diploid/aneuploid neoplastic cell population p53 protein expression was significantly (p < 0.01) higher in the aneuploid cell subpopulation. In conclusion, our study suggests that overexpression of p53 is present mainly in the most biologically aggressive forms of HSTS and may therefore represent a neoplastic progression index possibly useful for prognostic purposes.

High frequency of EBV association with non-random abnormalities of the chromosome region 1q21-25 in AIDS-related Burkitt's lymphoma-derived cell lines.

Chromosome 1q abnormalities represent the second most frequent cytogenetic lesion of Burkitt lymphoma (BL) and acute lymphoblastic leukemia (ALL)-L3. The most frequent change is partial duplication of the long arm of chromosome 1, involving variable bands but consistently including 1q23. Among AIDS-related BL similar chromosome 1q abnormalities have also been found. We have now characterized in detail the chromosome 1q abnormalities of 4 AIDS-BL cell lines and compared them to other molecular features of the tumor clone, namely infection by Epstein Barr virus (EBV). Immunophenotypic characteristics were also assessed by conventional in situ immunocytochemical and flow cytometric procedures. The B-cell origin of all cell lines was demonstrated by the expression of B-cell-restricted markers (e.g., CD19). Analysis of Ig light chains confirmed their monoclonal nature. The t(8;14) was present in 3 of the 4 lines, whereas variant translocation t(8;22) was detected in the remaining cell line. Additional chromosomal changes were found in all cases, with chromosome 1 being involved in all. Structural changes encompassed in each case the 1q21-25 bands, in either duplication or partial trisomy. EBER ISH studies identified EBV association in 3 of the 4 AIDS-BL cell lines in contrast to previous studies of BL of immunocompetent individuals. Our findings of a high frequency of chromosome 1q abnormalities in EBV-infected AIDS-related BL cell lines demonstrate that such chromosomal abnormality and EBV positivity are not mutually exclusive and are possibly independent factors, whereas their close association in AIDS may be related to the immunodeficiency.

Diagnostic and biological determinants in undifferentiated and poorly differentiated ovarian carcinomas.

Six ovarian undifferentiated carcinomas (UCs) and 19 poorly differentiated serous (14 cases) and endometrioid (5 cases) carcinomas with areas of solid diffuse carcinomas have been considered for the study. Pathological findings were analyzed in conjunction with molecular analysis concerning the structure and expression of nm23-H1 gene. Differences in the frequency of loss of heterozigosity (LOH) of this gene have been observed between the two groups, UCs displaying lower percentage of LOH (1/5) as compared to poorly differentiated tumors (17/17). The remaining 3 cases (1 UC and 2 poorly differentiated carcinomas) were homozygotes, i.e., noninformative. UCs might occur as a consequence of cellular dedifferentiation, being at the end of the differentiation spectrum of epithelial ovarian tumors. Nevertheless, this study suggests that, in a fraction of cases, UCs could represent a distinct entity not involved in the malignant progression, associated with peculiar DNA anomalies, one possibly being that of the nm23-H1 deletion. In other words, a noticeable subset of UCs, not harboring nm23-H1 alterations, may be histologically uncommitted "ab initio". Moreover, nm23-H1 LOHs could be considered early events in the ovarian carcinogenesis, because similar molecular patterns were found both in primary and metastatic sites of the same tumor.

Genetic characterization of HHV-8/KSHV-positive primary effusion lymphoma reveals frequent mutations of BCL6: implications for disease pathogenesis and histogenesis.

Human herpesvirus-8/Kaposi sarcoma-associated herpesvirus-positive primary effusion lymphoma (PEL) is a recently identified B-cell non-Hodgkin lymphoma category characterized by liquid growth in the serous body cavities. Apart from viral infection, no genetic alteration is known to be associated with PEL and no recurrent cytogenetic abnormality has been identified in these lymphomas. Yet the consistent monoclonality of PEL indicates that the disease is not solely a virus-driven proliferation. Here we report that PEL is associated with a high frequency of mutations of BCL6 5' noncoding regions, and we identify karyotypic abnormalities that may be recurrently involved in these lymphomas. Mutations of BCL-6 5' noncoding regions occurred in 8/13 PEL. Mutations occurred in the absence of BCL6 gross rearrangements were often multiple in the same patient (7/8 mutated cases), and occurred in both HIV-positive and HIV-negative individuals. Since BCL6 mutations are regarded as a genetic marker of B-cell transition through the germinal center (GC), these data are consistent with histogenetic derivation of PEL from GC or post-GC B-cells. Cytogenetic and FISH analysis of seven PEL cell lines showed frequent occurrence of complete or partial trisomy 12 (7/7 cases), trisomy 7 (4/7 cases), and abnormalities of bands Iq21-25 (5/7 cases).

Reed-Sternberg cells of classical Hodgkin's disease react with the plasma cell-specific monoclonal antibody B-B4 and express human syndecan-1.

Although the cellular origin of Reed-Sternberg (RS) cells of classical Hodgkin's disease (HD) has been a controversial issue for many years, recent immunophenotypic and molecular studies have suggested that RS cells of a subset of classical HD cases may be related to B cells. To further define the immunophenotypic features and the differentiation stage of RS cells, a series of 56 HD samples, including both nodular lymphocyte predominance (LP) (eight cases) and classical HD (nodular sclerosis [NS], 32 cases; mixed cellularity [MC], 16 cases) with a non-T-cell phenotype, were evaluated for the immunohistochemical expression of the B-B4 antigen, a specific marker for terminally differentiated B cells. Because the cDNA of the B-B4 antigen encodes syndecan-1, a member of a family of transmembrane heparan sulfate proteoglycans thought to be involved in binding cells of the B lineage to the interstitial matrix, the B-B4 immunoreactivity was correlated with the expression of syndecan-1 in HD-derived cell lines (L428, KM-H2), as detected by both reverse transcriptase polymerase chain reaction (RT-PCR) studies and Western blotting. Our results show that B-B4 reacts with RS cells and their morphological variants of all cases of classical HD, irrespective of their antigenic phenotype (B, undetermined), albeit at a varying degree of cellular expression. Notably, a high reactivity and staining intensity for the B-B4 monoclonal antibody (MoAb) was restricted to tumor cells from NS HD. In cases of the latter subtype, B-B4 positivity was also found in sclerosis-trapped spindle cells (fibrocytes/fibroblasts). Conversely, the putative tumor cells of nodular LP HD were consistently unreactive with the B-B4 MoAb. Finally, we have demonstrated by RT-PCR, flow cytometry, and Western blotting that cultured RS cells, of B and undetermined phenotype, express syndecan-1 mRNA and produce a form of syndecan-1, recognized by the B-B4 MoAb, which is predominantly associated with glycosaminoglycans and is present at the cell surface. Our detection of the plasma cell-specific antigen B-B4 (syndecan-1) on tumor cells of classical HD further supports that RS cell progenitors may be related to germinal/postgerminal center mature B cells and suggests that expression of syndecan-1 may contribute to some of the typical biologic and histopathologic features of classical HD, with a special regard to the NS subtype.

Establishment of HHV-8-positive and HHV-8-negative lymphoma cell lines from primary lymphomatous effusions.

Primary lymphomatous effusions are represented by cases of non-Hodgkin's lymphoma (NHL) which grow in liquid phase in the serous body cavities in the absence of solid tumour masses. Based on morphologic, immunophenotypic, virologic and genotypic features, primary lymphomatous effusions are distinguished into body cavity-based lymphoma (BCBL), Burkitt's lymphoma (BL) and immunoblastic large-cell lymphoma. The histogenesis and pathogenesis of primary lymphomatous effusions are virtually unclarified. In this study, we have established 2 cell lines (CRO-AP/1 and CRO-AP/2) representative of 2 distinct categories of primary lymphomatous effusion, BCBL (CRO-AP/2) and BL (CRO-AP/1). Both CRO-AP/1 and CRO-AP/2 carry monoclonal re-arrangements of the immunoglobulin genes which are identical to those of the respective parental tumours. Consistent with its BCBL origin, CRO-AP/2 is characterised by a non-B, non-T phenotype and harbours infection by HHV-8 (approx. 100 viral copies/cell) and Epstein-Barr virus. Conversely, CRO-AP/1 expresses several B cell-associated antigens, lacks HHV-8 infection and carries the genetic hallmark of BL, i.e., a chromosomal breakpoint of band 8q24. CRO-AP/1 and CRO-AP/2 may be valuable for the biologic characterization of primary lymphomatous effusions, particularly since the number of available cell lines derived from such lymphomatous effusions is extremely limited.