AIDS-related cancer in the era of highly active antiretroviral therapy (HAART): a model of the interplay of the immune system, virus, and cancer. "On the offensive--the Trojan Horse is being destroyed"--Part B: Malignant lymphoma

An Epigenetic LINE-1-Based Mechanism in Cancer

In the last fifty years, large efforts have been deployed in basic research, clinical oncology, and clinical trials, yielding an enormous amount of information regarding the molecular mechanisms of cancer and the design of effective therapies. The knowledge that has accumulated underpins the complexity, multifactoriality, and heterogeneity of cancer, disclosing novel landscapes in cancer biology with a key role of genome plasticity. Here, we propose that cancer onset and progression are determined by a stress-responsive epigenetic mechanism, resulting from the convergence of upregulation of LINE-1 (long interspersed nuclear element 1), the largest family of human retrotransposons, genome damage, nuclear lamina fragmentation, chromatin remodeling, genome reprogramming, and autophagy activation. The upregulated expression of LINE-1 retrotransposons and their protein products plays a key role in these processes, yielding an increased plasticity of the nuclear architecture with the ensuing reprogramming of global gene expression, including the reactivation of embryonic transcription profiles. Cancer phenotypes would thus emerge as a consequence of the unscheduled reactivation of embryonic gene expression patterns in an inappropriate context, triggering de-differentiation and aberrant proliferation in differentiated cells. Depending on the intensity of the stressing stimuli and the level of LINE-1 response, diverse degrees of malignity would be generated.

Recycling the Purpose of Old Drugs to Treat Ovarian Cancer

The main challenge in ovarian cancer treatment is the management of recurrences. Facing this scenario, therapy selection is based on multiple factors to define the best treatment sequence. Target therapies, such as bevacizumab and polymerase (PARP) inhibitors, improved patient survival. However, despite their achievements, ovarian cancer survival remains poor; these therapeutic options are highly costly and can be associated with potential side effects. Recently, it has been shown that the combination of repurposed, conventional, chemotherapeutic drugs could be an alternative, presenting good patient outcomes with few side effects and low costs for healthcare institutions. The main aim of this review is to strengthen the importance of repurposed drugs as therapeutic alternatives, and to propose an in vitro model to assess the therapeutic value. Herein, we compiled the current knowledge on the most promising non-oncological drugs for ovarian cancer treatment, focusing on statins, metformin, bisphosphonates, ivermectin, itraconazole, and ritonavir. We discuss the primary drug use, anticancer mechanisms, and applicability in ovarian cancer. Finally, we propose the use of these therapies to perform drug efficacy tests in ovarian cancer ex vivo cultures. This personalized testing approach could be crucial to validate the existing evidences supporting the use of repurposed drugs for ovarian cancer treatment.

Meningiomatosis in an AIDS Patient Receiving Highly Active Antiretroviral Therapy (HAART)

INTRODUCTION

Currently, AIDS is the worldwide leading cause of death among 15- to 59-year-old individuals. This trend has had particularly harsh social and economic consequences in sub-Saharan Africa, where more than half of global AIDS deaths take place. In the United States, an estimated 1.2 million people are infected with HIV. In 2012, a worldwide estimate of 1.7 million deaths due to AIDS-related causes was reported.About 10% to 12% of all AIDS patients will develop intracranial tumors. Differential diagnosis should rule out brain tumors such as central nervous system lymphoma and gliomas, as well as infectious processes such as toxoplasmosis, tuberculosis, and cryptococcosis.

CASE REPORT

A 27-year-old homosexual man was referred to our care center after 2 months of disabling left frontal headache. Upon AIDS diagnosis, the patient was given abacavir (ABC), lamivudine (3TC), and efavirenz (EFV), but he discontinued the treatment after 9 months and failed to attend follow-up appointments. Three years later, the patient returned to the hospital and received ABC, 3TC, and lopinavir/ritonavir (LPV/r). On admission, computed tomographic scan reported multiple contrast-enhancing lesions compatible with meningiomas. The patient underwent uncomplicated surgical resection of the frontal basal lesion originating in the left olfactory bulb. No new neurological deficits were reported during the postoperative stay.

CONCLUSIONS

According to a literature revision, it is likely that associated meningiomas are more aggressive in AIDS patients. Severe immunosuppression and the HIV-Tat protein may be involved in the pathogenesis of tumoral growth.

An uncommon presentation of HIV-related lymphoma

Although highly active antiretroviral therapy has improved the clinical course of patients with HIV, this population remains at a significantly increased risk for non-Hodgkin's lymphoma (NHL). Spinal cord compression is a rare presentation of NHL, regardless of the patient population. We encountered a patient with HIV-related NHL who presented with a thoracic spinal cord compression and had a complicated clinical course as a result of the atypical presentation.

Endothelial cell- and lymphocyte-based in vitro systems for understanding KSHV biology

Kaposi sarcoma (KS), the most common AIDS-associated malignancy, is a multifocal tumor characterized by deregulated angiogenesis, proliferation of spindle cells, and extravasation of inflammatory cells and erythrocytes. Kaposi sarcoma-associated herpesvirus (KSHV; also human herpesvirus-8) is implicated in all clinical forms of KS. Endothelial cells (EC) harbor the KSHV genome in vivo, are permissive for virus infection in vitro, and are thought to be the precursors of KS spindle cells. Spindle cells are rare in early patch-stage KS lesions but become the predominant cell type in later plaque- and nodular-stage lesions. Alterations in endothelial/spindle cell physiology that promote proliferation and survival are thus thought to be important in disease progression and may represent potential therapeutic targets. KSHV encodes genes that stimulate cellular proliferation and migration, prevent apoptosis, and counter the host immune response. The combined effect of these genes is thought to drive the proliferation and survival of infected spindle cells and influence the lesional microenvironment. Large-scale gene expression analyses have revealed that KSHV infection also induces dramatic reprogramming of the EC transcriptome. These changes in cellular gene expression likely contribute to the development of the KS lesion. In addition to KS, KSHV is also present in B cell neoplasias including primary effusion lymphoma and multicentric Castleman disease. A combination of virus and virus-induced host factors are similarly thought to contribute to establishment and progression of these malignancies. A number of lymphocyte- and EC-based systems have been developed that afford some insight into the means by which KSHV contributes to malignant transformation of host cells. Whereas KSHV is well maintained in PEL cells cultured in vitro, explanted spindle cells rapidly lose the viral episome. Thus, endothelial cell-based systems for studying KSHV gene expression and function, as well as the effect of infection on host cell physiology, have required in vitro infection of primary or life-extended EC. This chapter includes a review of these in vitro cell culture systems, acknowledging their strengths and weaknesses and putting into perspective how each has contributed to our understanding of the complex KS lesional environment. In addition, we present a model of KS lesion progression based on findings culled from these models as well as recent clinical advances in KS chemotherapy. Thus this unifying model describes our current understanding of KS pathogenesis by drawing together multiple theories of KS progression that by themselves cannot account for the complexities of tumor development.

The impact of highly active antiretroviral therapy on the incidence and outcomes of AIDS-defining cancers in Southern Alberta

OBJECTIVES

To determine the impact of highly active antiretroviral therapy (HAART) on the incidence and outcomes of Kaposi's sarcoma (KS), non-Hodgkin's lymphoma (NHL) and invasive cervical cancer/dysplasia in a well-defined geographical HIV-infected population between 1984 and 2005.

METHODS

A clinic database search, chart review and verification with public health records were undertaken for all AIDS-defining cancers diagnosed in Southern Alberta before and after the introduction of HAART.

RESULTS

A total of 2,137 patients with 9,265 person-years of HIV follow-up care were reviewed. One hundred and forty-three cases of KS, 64 cases of NHL and 11 cases of invasive cervical cancer/dysplasia were identified. KS and NHL together accounted for 15% of clinical presentations with an AIDS-defining illness that led to the HIV diagnosis. Following the introduction of HAART, the reduced number of severely immunocompromised patients was associated with 92 and 84% reductions in new diagnoses of KS and NHL, respectively, which were seen mainly in clinic patients declining or failing HAART. Crude reductions of 94 and 65% in mortality from KS and NHL, respectively, were also seen. The prevalences of KS, NHL and invasive cervical cancer/dysplasia have recently stabilized at 3, 1 and 5% of the population, respectively.

CONCLUSIONS

The introduction of HAART has dramatically reduced the incidence of KS and NHL and improved survival from these cancers for most patients in HIV care. However, patients still present with KS and NHL leading to their HIV diagnosis.

Lymphoma incidence patterns by WHO subtype in the United States, 1992-2001

Because the causes of most lymphoid neoplasms remain unknown, comparison of incidence patterns by disease subtype may provide critical clues for future etiologic investigations. We therefore conducted a comprehensive assessment of 114,548 lymphoid neoplasms diagnosed during 1992-2001 in 12 Surveillance, Epidemiology, and End Results (SEER) registries according to the internationally recognized World Health Organization (WHO) lymphoma classification introduced in 2001. Cases coded in International Classification of Diseases for Oncology, Second Edition (ICD-O-2), were converted to ICD-O-3 for WHO subtype assignment. Age-specific and age-adjusted rates were compared by sex and race (white, black, Asian). Age-adjusted trends in incidence were estimated by sex and race using weighted least squares log-linear regression. Diverse incidence patterns and trends were observed by lymphoid neoplasm subtype and population. In the elderly (75 years or older), rates of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma increased 1.4% and 1.8% per year, respectively, whereas rates of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) declined 2.1% per year. Although whites bear the highest incidence burden for most lymphoid neoplasm subtypes, most notably for hairy cell leukemia and follicular lymphoma, black predominance was observed for plasma cell and T-cell neoplasms. Asians have considerably lower rates than whites and blacks for CLL/SLL and Hodgkin lymphoma. We conclude that the striking differences in incidence patterns by histologic subtype strongly suggest that there is etiologic heterogeneity among lymphoid neoplasms and support the pursuit of epidemiologic analysis by subtype.

AIDS-Related Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) can develop in the setting of profound immunosuppression, including late-stage infection with HIV. The management of such patients has yet to be defined optimally and differs substantially from that of immunocompetent patients who have PCNSL. The clinical features, diagnosis, and management of AIDS-related PCNSL are reviewed. The authors focus on commonly encountered diagnostic and therapeutic dilemmas and explore some promises and pitfalls of Epstein-Barr virus-directed therapies.