Detection of human herpes virus type 8 DNA sequences as a valuable aid in the differential diagnosis of Kaposi's sarcoma

The occurrence of human herpes virus type 8 (HHV-8) DNA sequences was evaluated by polymerase chain reaction in 36 cases of cutaneous Kaposi's sarcoma (KS) (classic and associated with the acquired immunodeficiency syndrome) and in 88 pathologic entities that can histologically mimic KS, such as reactive and neoplastic vascular processes and lesions featuring focal or extensive spindle cell pattern. A positive reaction was detected in 16 (70%) of 23 samples of classic KS and 10 (77%) of 13 KS cases related to the acquired immunodeficiency syndrome. In particular, 4 (50%) of 8 samples in the patch stage were found to be positive, whereas in the plaque and nodular stages, HHV-8 DNA sequences were observed in 8 (67%) of 12 and 14 (87%) of 16 cases, respectively. KS cases that had yielded previous negative results were found to be positive for HHV-8 on nested polymerase chain reaction, except two cases of classic KS in the patch stage (6% of the total number of KS, 25% of cases in the patch stage). Reactive and neoplastic vascular processes and cutaneous lesions with a spindle cell component were consistently negative. HHV-8 detection by polymerase chain reaction can represent a valuable method for diagnosing KS, particularly in small skin biopsy samples that might show histologic overlap with non-KS lesions. In early patch stage lesions, however, the diagnostic value of the method is hampered by the occurrence of cases in which HHV-8 sequences are still undetectable.

Human herpesvirus 6 (HHV-6) ORF-1 transactivating gene exhibits malignant transforming activity and its protein binds to p53

The 357 amino acid open reading frame 1 (ORF-1), also designated DR7, within the SalI-L fragment of human herpesvirus 6 (HHV-6) exhibited transactivation of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) promoter and increased HIV-1 replication (Kashanchi et al., Virology, 201, 95-106, 1994). In the current study, the SalI-L transforming region was localized to the SalI-L-SH subfragment. Several ORFs identified in SalI-L-SH by sequence analysis were cloned into a selectable mammalian expression vector, pBK-CMV. Only pBK/ORF1 transformed NIH3T3 cells. Furthermore, cells expressing ORF-1 protein produced fibrosarcomas when injected into nude mice, whereas control cells, expressing either no ORF-1 protein or C-terminal truncated (after residue 172) ORF-1 protein, were not tumorigenic. Western blot analysis of proteins extracted from the tumors revealed ORF-1 protein. Additional studies indicated that ORF-1 was expressed in HHV-6-infected human T-cells by 18 h. Co-immunoprecipitation experiments showed that ORF-1 protein bound to tumor suppressor protein p53, and the ORF-1 binding domain on p53 was located between residues 28 and 187 of p53, overlapping with the specific DNA binding domain. Functional studies showed that p53-activated transcription was inhibited in ORF-1, but not in truncated ORF-1, expressing cells. Importantly, the truncated ORF-1 mutant also failed to cause transformation. Analysis of several human tumors by PCR revealed ORF-1 DNA sequences in some angioimmunoblastic lymphadenopathies, Hodgkin's and non-Hodgkin's lymphomas and glioblastomas. The detection of ORF-1 sequences in human tumors, while not proof per se, is a prerequisite for establishing its role in tumor development. Taken together, the results demonstrate that ORF-1 is an HHV-6 oncogene that binds to and affects p53. The identification of both transforming and transactivating activities within ORF-1 is a characteristic of other viral oncogenes and is the first reported for HHV-6.

P53 gene mutations in chronic myelogenous leukemia medullary and extramedullary blast crisis

Molecular alterations of the P53 gene were investigated in 27 unselected patients with chronic myelogenous leukemia (CML) blast crisis. A rearrangement of the P53 gene was evident by Southern blotting in 3 cases, one of which also showed the same alteration in the chronic phase. Single strand conformation polymorphism and sequencing analysis showed point mutations in 4 blast crisis cases. Of interest, P53 point mutations were evident in all the 3 cases of extramedullary blast crisis examined and the same point mutation was found in the myeloblastoma tissues and in the subsequent peripheral blast cells. These data indicate that: a) P53 gene mutations occur in a significant but not a large number of CML acute phase cases; b) P53 gene point mutations seem to correlate strongly with the infrequent extramedullary presentation of the blast crisis; c) the presence of the same P53 gene point mutation in extramedullary and bone marrow blast cells confirms the common clonal origin of the two cellular populations.

Sensitive detection of circulating breast cancer cells by reverse-transcriptase polymerase chain reaction of maspin gene

BACKGROUND

Maspin, a recently identified protein related to the family of serpins, is believed to play a role in human breast cancer. In an effort to improve the present methods of detection, we have developed a reverse-transcriptase polymerase chain reaction (RT-PCR) assay for maspin transcript to identify small numbers of mammary carcinoma cells in the peripheral blood and bone marrow of patients with breast cancer.

PATIENTS AND METHODS

Five non-neoplastic mammary tissue samples, 13 breast cancer specimens as well as 17 peripheral blood and 4 bone marrow samples from normal subjects were screened for the presence of maspin mRNA by RT-PCR. The same assay was applied to peripheral blood or bone marrow samples obtained from 29 patients with stages I to IV breast cancer.

RESULTS

By RT-PCR it was possible to amplify maspin mRNA in all of the primary and metastatic breast cancer specimens, but in none of the normal hemopoietic samples from healthy donors. Thus, detection of maspin transcript in the peripheral blood or marrow of a patient known to have breast cancer is indicative of the presence of mammary carcinoma cells. In reconstitution experiments, maspin RT-PCR reliably detected 10 mammary carcinoma cells in 1 million normal peripheral-blood mononuclear cells (PBMCs). None of the 9 patients with stages I, II, or III breast cancer had maspin transcript in peripheral blood. Of note, 3 of 9 patients with stage IV breast cancer receiving systemic therapy at the time of sample collection, but only 1 of 11 patients with stage IV not receiving therapy, had detectable maspin transcript in peripheral blood. Moreover, 3 marrow specimens from stage IV patients tested positive by this assay.

CONCLUSIONS

This pilot study suggests that maspin RT-PCR assay is a sensitive, specific and sufficiently rapid method for detection of small numbers of circulating cells and marrow micrometastases in breast cancer patients. The possibility of applying this assay in the detection of tumor cell contamination of both marrow and stem-cell apheresis harvests of breast cancer patients merits further investigation.

Additional neoplasms and HCV infection in low-grade lymphoma of MALT type

Several chronic inflammatory conditions and genetic alterations are likely to be involved in the pathogenesis of low-grade lymphoma of MALT type. In a well-characterized series of 27 patients with low-grade lymphoma of MALT type, we studied: (1) the incidence of other neoplasms, which might be indicative of genetic instability, apparently a characteristic of this disease; (2) the prevalence of serologic and molecular markers of HCV infection, which has been found in association with other lymphoproliferative disorders. Three patients had one or more additional cancers; a total of eight tumours, five of which occurred in the same patient, suggests the presence of some genetic instability in at least some cases of the disease. Rather unexpectedly, anti-HCV antibodies and HCV RNA sequences were documented in 50% of the patients examined, without elevation of serum transaminases. Of interest, the two patients with parotid and conjunctival MALT lymphomas, respectively, with a previous history of Sjögren's syndrome, were HCV positive. We suggest, for the first time, that HCV may be considered, in addition to Helicobacter pylori, as another potential infectious co-factor in the multistep pathogenesis of low-grade lymphomas of MALT type.

Frequency and distribution of herpesvirus-like DNA sequences (KSHV) in different stages of classic Kaposi's sarcoma and in normal tissues from an Italian population

The frequency and distribution of herpesvirus-like DNA sequences (KSHV) were investigated by PCR in the pathologic skin lesions of a series of 22 HIV-negative elderly patients with classic Kaposi's sarcoma (KS) from Italy, one of the few regions of the world where classic KS is prevalent. Viral sequences were clearly identifiable in 15 cases, in particular in 2 of 5 patch, in 3 of 6 plaque and in 10 of 11 nodular lesions. Our findings confirm the association of these herpesvirus-like DNA sequences with KS in unrelated populations, providing evidence of the putative KS-associated agent in all different histologic lesions of the disease, mainly in the nodular stage. The search for other herpesviruses by PCR showed that Epstein-Barr virus (EBV) sequences were present in 7 of 22 pathologic skin lesions. In 4 cases, both EBV and KSHV were present. On the contrary, all 22 classic KS specimens were negative for human herpesvirus-6 sequences. Two of 3 patch and the 1 nodular lesions from AIDS-related KS patients examined were positive for KSHV but negative for both EBV and HHV-6 sequences. Furthermore, we evaluated the prevalence of KSHV sequences in the normal population of the same geographical area. Thirteen peripheral blood mononuclear cell samples, 9 salivary gland tissues and 6 saliva samples from healthy subjects were invariably found negative for KSHV, using the same PCR technique. Of interest, 2 of 11 hyperplastic tonsils harboured these herpesvirus-like sequences, suggesting that, like other herpesviruses, the KS- associated agent may be harboured in a proportion of normal individuals and tonsils may represent at least one of the possible reservoirs of this putative lymphotropic gamma-herpesvirus in vivo.

Human herpesvirus-8 DNA sequences in human immunodeficiency virus-negative angioimmunoblastic lymphadenopathy and benign lymphadenopathy with giant germinal center hyperplasia and increased vascularity

Human herpesvirus-8 (HHV-8) DNA sequences have been reported to be strictly associated not only with various forms of Kaposi's sarcoma but also with an unusual subgroup of acquired immunodeficiency syndrome (AIDS)-related B-cell lymphomas. A possible relation of this putative virus also with multicentric Castleman's disease (MCD) has been recently suggested. We used polymerase chain reaction to look for the presence of HHV-8 sequences in a well characterized series of benign, atypical, and malignant lymphoid tissues from 45 Hodgkin's disease and 43 non-Hodgkin's lymphoma (NHL) cases, as well as from 5 MCD, 15 angioimmunoblastic lymphadenopathy (AILD), and 23 benign lymphadenopathy cases. Among the 38 AIDS-related lymphoid lesions, only 1 NHL and 1 persistent generalized lymphadenopathy (PGL) case were positive. Furthermore, among the 92 non-AIDS-related lymphoproliferative disorders, HHV-8 sequences were detected in 3 classic AILD cases and in 4 reactive lymphadenopathies. Six of 9 HHV-8 positive lymphoid lesions (1 NHL, 1 PGL, 1 AILD, and 3 reactive lymphadenopathy cases) were also positive for Epstein-Barr viral sequences. The four human immunodeficiency virus (HIV) negative lymphadenopathies positive for HHV-8 sequences showed an almost identical histology, characterized by a predominantly follicular lesion, with giant germinal center hyperplasia, and increased vascularity, resembling HIV-related lymphadenopathy and MCD. Our results, while providing the first evidence of the presence of HHV-8 sequences in AILD cases, suggest a possible association of these herpes viral sequences with a distinct histologic type of non-neoplastic lymphadenopathy, not associated with other common herpes infections.

The new lymphotropic herpesviruses (HHV-6, HHV-7, HHV-8) and hepatitis C virus (HCV) in human lymphoproliferative diseases: an overview

Considerable evidence has been accumulating in favor of a possible involvement of viral agents in the pathogenesis of human lymphomas. The most recent proposal for a lymphoma classification, the Revised European-American Classification, emphasized for the first time the pathogenetic importance of two viruses, namely Epstein-Barr virus (EBV) and human T lymphotropic virus I (HTLV-I) in the development of certain lymphoid neoplasias. However, in the last ten years new viral agents possibly related to lymphoproliferative activity have been discovered: three herpesviruses [human herpesvirus-6 (HHV-6), -7 (HHV-7) and -8 (HHV-8)] and a flavivirus, HCV. HHV-6 was isolated from the peripheral blood of patients with lymphomas and a possible role for this beta-herpesvirus in Hodgkin's disease and in angioimmunoblastic lymphadenopathy (AILD) has emerged from serological and molecular studies. HHV-7, a beta-herpesvirus genetically close to HHV-6, has not yet been found in a human disease but it utilizes CD4 as a receptor on the lymphocyte surface. Only partial HHV-8 genomic sequences have been identified so far, suggesting a genetic homology with members of the gamma-herpesvirus family, including EBV. HHV-8 sequences have been identified for the first time in all forms of Kaposi's sarcoma as well as in a variety of lymphoid disorders, including body-cavity-based non Hodgkin's lymphomas, Castleman's disease, AILD and a type of HIV-negative reactive lymphadenopathy with peculiar histologic features. Finally, after its identification as the major cause of post-transfusion and sporadic non-A, non-B hepatitis, HCV has revealed a lymphotropism both in vitro and in vivo. A strong association between HCV infection and a benign lymphoproliferative disease, essential mixed cryoglobulinemia type II, has clearly emerged both from serological and molecular studies. A possible role for this viral infection in B-cell non Hodgkin's lymphomas not associated with cryoglobulinemia has also been proposed recently. The present work offers an overview of the huge amount of experimental and clinical observations supporting the possible involvement of these new lymphotropic viruses in human lymphoproliferative diseases.

An encephalitic episode in a multiple sclerosis patient with human herpesvirus 6 latent infection

All the human herpesviruses may cause central nervous system (CNS) diseases, including benign aseptic meningitis or fatal encephalitis. It has recently been stated that human herpesvirus 6 (HHV-6) may also be neuropathogenic in children after primary infection, while in the adult, cases of fatal encephalitis have been reported only in immune-compromised hosts such as AIDS patients, and in one case of an immunosuppressed bone marrow transplant patient. We describe a multiple sclerosis (MS) patient, carrier of HHV-6 latent infection, who experienced an acute inflammation of the CNS diagnosed as encephalitis. HHV-6 specific genomic sequences have been detected by PCR in the patient's PBMCs DNA collected before and during the encephalitis. The PCR performed in the CSF in course of the acute episode was positive, while the CSF collected before the encephalitis was negative. This finding is consistent with an acute encephalopathy caused by the reactivation of a HHV-6 latent infection within the CNS, in a patient with altered immune response due to MS.

Hepatitis C virus infection in subsets of neoplastic lymphoproliferations not associated with cryoglobulinemia

Hepatitis C virus (HCV) is both hepatotropic and lymphotropic and a clear-cut association has been proposed between HCV infection and mixed cryoglobulinemia (MC), a benign lymphoproliferative disorder, which sometimes evolves into a frank malignant B cell non-Hodgkin's lymphoma (B-NHL). Moreover, in the presence of antibodies to HCV, as well as of HCV-specific genomes has been reported in the sera of over 37% patients with B-NHL, not associated with MC. Thus, we decided to perform both a serologic and a molecular study to give insights into a possible relationship between HCV infection and neoplastic lymphoproliferations. We used ELISA and RIBA tests to show that anti-HCV antibodies were present in the serum of 29 out of 69 unselected B-NHL patients (42%), while seropositivity in a healthy population was about 1%. The prevalence of anti-HCV antibodies was low in definite subsets of B lymphoid disorders, including multiple myeloma, Waldenström's macroglobulinemia and monoclonal gammopathies of undetermined significance. Then, using reverse transcriptase polymerase chain reaction, we detected HCV sequences directly in the pathologic lymph node biopsies in 13 out of 34 B-NHL cases, and in particular in six out of eight low-grade lymphomas of MALT type and in five out of eight centroblastic-centrocytic follicular lymphomas. In contrast, the peripheral blood samples from 10 B cell chronic lymphocytic leukemia patients resulted negative for the presence of HCV genomes. Similarly, viral sequences were absent in 10 T cell NHL, while only one out of the 14 Hodgkin's disease cases tested resulted positive. Finally, we used a PCR-based assay to characterize the genotypes (I-IV) present in the positive lymphomatous tissues. The presence of both serologic and molecular markers of HCV infection in a high percentage of certain types of B-NHL, not associated with cryoglobulinemia, and its absence from other lymphoproliferative diseases extends the spectrum of HCV-associated lymphoproliferations arguing in favor of some role of this viral infection in the pathogenesis of the malignant proliferation of definite B lymphoid populations.

Human herpesvirus-6: a survey of presence and distribution of genomic sequences in normal brain and neuroglial tumors

In an attempt to study the frequency and distribution of human herpesvirus-6 (HHV-6) infection both in normal and neoplastic brain tissues in vivo, polymerase chain reaction was used to look for HHV-6 genomes: 1) in samples, obtained at necropsy, from different regions of the brain of immunocompetent adult subjects and of patients who died of AIDS; 2) in the surgical biopsies of a well-characterized series of primary brain tumors of neuroglial origin. HHV-6-specific sequences were identified in six of nine brain samples from immunocompetent subjects, and in four of seven brain samples from AIDS patients. Viral sequences were identified in the specimens derived either from the grey (frontal cortex and basal ganglia) or from the periventricular white matter. HHV-6 DNA was found only in 6 of the 37 primary brain tumor biopsies examined. This study provides for the first time molecular evidence of a wide distribution of HHV-6 infection in the brain tissues of a high proportion of subjects, both in normal and in impaired immunity. In this large series of tumor biopsies the presence of HHV-6 genomic sequences is a rare phenomenon, arguing against a major role of this herpesvirus in the pathogenesis of primary brain tumors of neuroglial origin in immunocompetent subjects.

Targeted integration of human herpesvirus 6 in the p arm of chromosome 17 of human peripheral blood mononuclear cells in vivo

Out of 64 cases of non-Hodgkin's lymphomas (NHL), 55 cases of Hodgkin's disease (HD) and 31 cases of multiple sclerosis (MS), 2 NHL, 7 HD and 1 MS cases were found positive by polymerase chain reaction (PCR) for the presence of HHV-6 sequences in pathologic lymph nodes of the lymphomas and in peripheral blood mononuclear cells (PBMCs) of MS. A further analysis of the PBMCs of the PCR positive cases by standard Southern blot technique revealed only 2 NHL, 3 HD and 1 MS cases as positive, indicating that these six patients have an unusually high viral copy number in the PBMCs. Restriction analysis, carried out using probes representative of different regions of the virus, showed that three cases retain only a deleted portion of the viral genome. In the remaining three cases a complete viral genome was present, containing the right end sequences in which the rep-like gene, possibly crucial to the viral and cellular life cycle, is located. The analysis by pulsed field gel electrophoresis (PFGE) of the total DNA of the PBMCs obtained directly, without culture from PBMCs of these last three cases (1 NHL, 1 HD, and 1 MS), using the same probes, showed the absence of free viral molecules and the association of viral sequences with high molecular weight DNA. These results are consistent with in vivo integration of the entire virus in the cellular genome. A further study of the same patients with chromosome fluorescence in situ hybridization (FISH) showed in all the three cases the presence of a specific hybridization site, located at the telomeric extremity of the short arm of chromosome 17 (17p13), suggesting that this location is at least a preferred site of an infrequent, but possibly biologically important, integration phenomenon.

p53 gene point mutations in relation to p53 nuclear protein accumulation in colorectal cancers

It is known that structural alterations of the p53 tumour suppressor gene cause malignant transformation and tumour progression in colorectal mucosa. In this study, 38 colorectal cancers were analysed for mutations detected in the p53 gene by single-strand conformational polymorphism and DNA sequence analysis, and the results were compared with p53 protein expression detected by immunohistochemistry. A very strict association (P < 0.0001) was found between genetic alterations and protein accumulation, as detected by the PAb 1801 monoclonal antibody. p53 expression and gene mutations were more frequent in rectal than in colonic cancers. No relation was observed with Dukes' stage, even though most of the mutations were at exon 7 in Dukes' A-B cancers and almost all mutations at exon 8 were observed in Dukes' C-D cancers. DNA ploidy was not generally associated with p53 protein expression or gene mutations. However, 83 per cent of cases with exon 5 and 6 mutations were diploid or near-diploid and 71 per cent of cases with mutations at exons 7 and 8 were aneuploid. Tumours with p53 gene mutations at exon 5 had a higher median [3H]thymidine labelling index (17 per cent) than those with mutations at exons 6, 7, and 8 (11.8 per cent).

Detection of PML-RAR alpha fusion transcript in Ph positive leukemia with acute promyelocytic phenotype lacking the t(15;17) cytogenetic abnormality

A 39-year-old woman was diagnosed with acute promyelocytic leukemia (APL) with disseminated intravascular coagulation syndrome. The hematologic examination showed a morphologic, cytochemical, and immunophenotypic picture typical of an APL, with a marked leukocytosis and a mixed population of hypergranular and microgranular promyelocytes. The cytogenetic analysis showed a 46,XX,t(9;22) karyotype, without any alterations of chromosomes 15 and 17. The t(15;17) translocation was not evident in FISH experiments, while a molecular analysis revealed the presence of a PML-RAR alpha chimera.