HTLV-associated diseases: human retroviral infection and cutaneous T-cell lymphomas

The implications of cell-free DNAs derived from tumor viruses as biomarkers of associated cancers

Cancer is still ranked as a leading cause of death according to estimates from the World Health Organization (WHO) and the strong link between tumor viruses and human cancers have been proved for almost six decades. Cell-free DNA (cfDNA) has drawn enormous attention for its dynamic, instant, and noninvasive advantages as one popular type of cancer biomarker. cfDNAs are mainly released from apoptotic cells and exosomes released from cancer cells, including those infected with viruses. Although cfDNAs are present at low concentrations in peripheral blood, they can reflect tumor load with high sensitivity. Considering the relevance of the tumor viruses to the associated cancers, cfDNAs derived from viruses may serve as good biomarkers for the early screening, diagnosis, and treatment monitoring. In this review, we summarize the methods and newly developed analytic techniques for the detection of cfDNAs from different body fluids, and discuss the implications of cfDNAs derived from different tumor viruses in the detection and treatment monitoring of virus-associated cancers. A better understanding of cfDNAs derived from tumor viruses may help formulate novel anti-tumoral strategies to decrease the burden of cancers that attributed to viruses. This article is protected by copyright. All rights reserved.

Adult T-cell leukemia/lymphoma can be indistinguishable from other more common T-cell lymphomas. The University of Miami experience with a large cohort of cases

Adult T-cell leukemia/lymphoma, an aggressive T-cell neoplasm, is causally linked to human T-cell lymphotropic virus type 1 and based on this association has a distinct geographic distribution. In our United States-based practice, whose population is enriched for immigrants from human T-cell lymphotropic virus type 1 endemic areas, we have identified that a subset of adult T-cell leukemia/lymphoma, in the absence of human T-cell lymphotropic virus type 1 identification, are indistinguishable from other more common T-cell neoplasms. We retrospectively gathered serology results for anti-human T-cell lymphotropic virus type 1/2 antibody in patients diagnosed with T-cell neoplasms at our institution. A total of 220 human T-cell lymphotropic virus type 1/2 positive patients with T-cell neoplasms were identified; 199 (91%) were correctly classified as adult T-cell leukemia/lymphoma or provisionally as peripheral T-cell lymphoma (serology testing pending). Twenty-one cases (9%) were initially misclassified, including the following: 13 presenting with skin +/- peripheral blood involvement and misclassified as mycosis fungoides/Sezary syndrome; 7 with lymphomatous disease, absence of leukemic involvement, and diffuse CD30 expression, misclassified as ALK- negative anaplastic large-cell lymphoma; 1 thought to represent T-prolymphocytic leukemia with TCL-1 gene rearrangement and diffuse marrow involvement. We also present an example of adult T-cell leukemia/lymphoma, which mimicked lymphoepithelioid variant of peripheral T-cell lymphoma also with diffuse marrow involvement. A subset of adult T-cell leukemia/lymphoma can closely mimic a variety of other more common T-cell neoplasms. Due to its extreme clinicopathologic heterogeneity, identification of adult T-cell leukemia/lymphoma requires a high level of suspicion based on patient demographic alone, which should prompt anti-human T-cell lymphotropic virus type 1/2 serology testing in all T-cell neoplasms developing in patients of appropriate demographic. Absence of high level of suspicion, adult T-cell leukemia/lymphoma is easily misclassified.

Role of infectious agents in cutaneous T-cell lymphoma: facts and controversies

The etiology of cutaneous T-cell lymphoma (CTCL) remains unknown, with potential infectious causes having been explored. This contribution evaluates the evidence suggesting an infectious etiology and pathogenesis of the disease, characterizes the relationships between various specific pathogens and CTCL, and discusses some of the difficulties in establishing a causal link between infectious agents and CTCL carcinogenesis. Researchers have evaluated CTCL specimens for evidence of infection with a variety of agents, including human T-lymphotropic virus, Epstein-Barr virus, human herpesvirus-8, and Staphylococcus aureus, although other pathogens also have been detected in CTCL. Although there is significant evidence implicating one or more infectious agents in CTCL, studies to date have not linked definitively any pathogen to disease development, and various studies have yielded conflicting results.

Cutaneous manifestations of lymphoma: a clinical guide based on the WHO classification. World Health Organization

Cutaneous lymphomas are a heterogeneous group of lymphomas that show variations in histology, immunophenotype, and prognosis. At the time of presentation, cutaneous lymphomas may be primary or may involve the skin as a secondary site of involvement. Primary cutaneous lymphomas, in many instances, are distinct from morphologically similar lymphomas arising in lymph nodes. Their natural history is often more indolent than nodal lymphomas, and for that reason, they often require different therapeutic approaches. A classification scheme should recognize those lymphomas that are unique to the skin, as well as those arising in other sites. The mode of presentation of a lymphoma is often an indication of underlying biological distinctions. However, organ-specific classification systems undermine communication among medical specialists. The World Health Organization classification of hematopoietic and lymphoid malignancies offers a comprehensive approach and proposes that lymphomas should be viewed as a list of individual diseases and that each disease can be defined by a constellation of morphological, biological, and clinical features. The current review will focus on the spectrum of primary and secondary cutaneous lymphomas, emphasizing those features of importance to the clinical oncologist.

Partial tolerance of subcutaneously transplanted xenogeneic tumour cell graft by Fas-mediated immunosuppression

Certain anti-Fas antibodies, such as RMF2, induce apoptosis of Fas-expressing cells. We applied the Fas/anti-Fas system to induce killing of Fas-expressing immunocytes with resultant immunosuppression. W7TM-1 tumour cells, a rat T-cell line, were inoculated subcutaneously in BALB/c mice and tumour growth was monitored in untreated mice and in mice treated with RMF2. Prior to treatment with RMF2, we examined the expression of Fas in isolated splenocytes and in tumour-infiltrating lymphocytes by flow cytometry and immunohistochemistry, respectively. There was a remarkable increase in Fas-positive lymphocytes, including natural killer (NK) cells, among splenocytes at day 5 after tumour cell inoculation. The number of Fas-positive infiltrating lymphocytes also increased markedly, from day 5 to day 10. We then examined whether RMF2 could induce apoptosis of Fas-positive activated lymphocytes isolated from the spleen at day 5 in vitro. Terminal deoxy (d) -UTP nick end labelling (TUNEL) and Annexin V staining methods showed apoptosis of isolated cells when incubated with RMF2, and typical apoptotic features were confirmed by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) staining. Furthermore, suppression of cellular and humoral immunity was noted in RMF2-treated mice by mixed lymphocyte reaction and assay of serum levels of immunoglobulin G, respectively. Finally, treatment of animals with RMF2 daily from day 5 to day 9 could maintain the tumour size, while the tumour mass began to diminish in untreated mice immediately after reaching a maximum size. We confirmed the enhancing effects of long-term treatment with RMF2, through the induction of immunosuppression, on the growth of unvascularized xenogeneic tumour cell grafts.

p53 tumor suppressor gene mutations in transformed cutaneous T-cell lymphoma: a study of 12 cases

The transformation of cutaneous T-cell lymphoma (t-CTCL) is an uncommon phenomenon that is associated with histopathologic changes and follows an aggressive course. The factors contributing to this transformation are poorly understood. The aim of this study was to analyze the p53 status in t-CTCL and to correlate it with disease outcome. The p53 status was investigated by immunohistochemistry, single-strand conformation polymorphism (SSCP) and DNA sequencing in 12 patients with t-CTCL. Eight mutations were detected; including four in exon 5, one in exon 6 and three in exon 7. Five were point mutations and three were deletions. Paired samples from nontransformed patch and plaque lesions showed no p53 over-expression. Eight disease-related deaths were reported, six to 23 months after transformation, all of which had p53 mutations. Three other patients with wild phenotype (WT-p53) were last reported alive with the disease 19-33 months after transformation (p < 0.0002). One other case had a p53 mutation but a short period of follow-up. Our results suggest that phenotypic changes of t-CTCL are frequently associated with genotype alterations in the p53 gene. Because 70% of the mutations detected were either G to C transversions or deletions, nucleotide-pairing mismatch and not DNA damage by UVB represents a likely mechanism for mutagenesis. Furthermore, the data may help in the design of gene transfer therapies that target the p53 molecule.