The histogenesis of Kaposi's sarcoma (KS) tumor spindle cells (SC) remains controversial but several immunohistochemical studies favor a lymphatic origin. Twenty KS surgical biopsies were analyzed for the coexpression of LANA, CD34, LYVE-1, D2-40, VEGFR-2, VEGFR3 by using double or triple immunostaining. Most of the SC in both early and late KS expressed the lymphatic markers LYVE-1, D2-40 and VEGFR-3 and the blood vascular endothelial/endothelial precursor cell markers CD34 and endothelial stem cell marker VEGFR-2. All the LANA1 SC in early and late KS were LYVE-11, but only 75% of these LANA1 cells were CD341. The CD341/LANA1 cells increased from early-(68.8%) to late-stage KS (82.2%). However, approximately 18% of the LANA1 SC in early KS were CD342 but were LYVE-11, suggesting that resident lymphatic endothelial cells (LEC) are targeted for primary infection by human herpesvirus-8. This LANA1/LYVE-11/CD342 (resident LEC) cell population clearly decreased during the development of KS from early (18.7%) to late KS (2.9%). Thus, in late stages of KS, most SC were LANA1/CD341/LYVE-11. However, in both early-and late-stage KS, approximately 18% of the SC were CD341/ LANA-/LYVE-12 and could represent newly recruited endothelial precursor cells, which become infected in the lesion and eventually undergo a phenotype switch expressing LEC markers. Our study apparently indicates that KS represents a unique variant of tumor growth with continues recruitment of tumor precursor cells as well as proliferation and decreased apoptosis of SC. ' 2006 Wiley-Liss, Inc.Key words: Kaposi's sarcoma; HHV-8; KSHV; LANA; lymphangiogenesis; lymphatic; vascular endothelium; immunohistochemistry Kaposi's sarcoma (KS) presents as a highly vascularized tumorlike lesion affecting primarily the skin but which during development also disseminates to lymphnodes and viscera. 1 The lesions develop from early stages of patch/plaque to late nodular tumor lesions, 2 with characteristic early infiltration of mononuclear inflammatory cells, formation of atypical small blood vessels and vascular slits (angiogenesis), extravasations of erythrocytes and increased appearance of so-called spindle cells (SC) regarded as the tumor cells. 3 Unlike metastatic cancers, KS may also develop as multicentric tumor lesions, each arising from a focal reactive lesion and appearance of endothelial SC. 4 In 1994, a new herpesvirus was identified, namely, KS-associated herpesvirus or human herpesvirus-8 (KSHV/HHV-8), 5 which subsequently also was found in the other clinicoepidemiological forms of KS, 6-8 i.e., classic KS, iatrogenic KS, endemic KS (EKS) as well as in some rare, often AIDS-associated lymphoid disorders as primary effusion lymphoma 9 and multicentric Castleman's disease. 10 The HHV-8 latency-associated nuclear antigen type 1 (LANA-1) is consistently expressed in infected cells and considered necessary for the maintenance of HHV-8 infection. 11 The histogenesis of KS remains controversial but several immunohistochemical studies favor an endothelial origin...

Summary Distinguishing Burkitt lymphoma (BL) from B cell lymphoma, unclassifiable with features intermediate between diffuse large B‐cell lymphoma (DLBCL) and BL (DLBCL/BL), and DLBCL is challenging. We propose an immunohistochemistry and fluorescent in situ hybridization (FISH) based scoring system that is employed in three phases – Phase 1 (morphology with CD10 and BCL2 immunostains), Phase 2 (CD38, CD44 and Ki‐67 immunostains) and Phase 3 (FISH on paraffin sections for MYC, BCL2, BCL6 and immunoglobulin family genes). The system was evaluated on 252 aggressive B‐cell lymphomas from Europe and from sub‐Saharan Africa. Using the algorithm, we determined a specific diagnosis of BL or not‐BL in 82%, 92% and 95% cases at Phases 1, 2 and 3, respectively. In 3·4% cases, the algorithm was not completely applicable due to technical reasons. Overall, this approach led to a specific diagnosis of BL in 122 cases and to a specific diagnosis of either DLBCL or DLBCL/BL in 94% of cases that were not diagnosed as BL. We also evaluated the scoring system on 27 cases of BL confirmed on gene expression/microRNA expression profiling. Phase 1 of our scoring system led to a diagnosis of BL in 100% of these cases.

Tanzania requires more health professionals equipped to tackle its serious health challenges. When it became an independent university in 2007, Muhimbili University of Health and Allied Sciences (MUHAS) decided to transform its educational offerings to ensure its students practice competently and contribute to improving population health. In 2008, in collaboration with the University of California San Francisco (UCSF), all MUHAS's schools (dentistry, medicine, nursing, pharmacy, and public health and social sciences) and institutes (traditional medicine and allied health sciences) began a university-wide process to revise curricula. Adopting university-wide committee structures, procedures, and a common schedule, MUHAS faculty set out to: (i) identify specific competencies for students to achieve by graduation (in eight domains, six that are inter-professional, hence consistent across schools); (ii) engage stakeholders to understand adequacies and inadequacies of current curricula; and (iii) restructure and revise curricula introducing competencies. The Tanzania Commission for Universities accredited the curricula in September 2011, and faculty started implementation with first-year students in October 2011. We learned that curricular revision of this magnitude requires: a compelling directive for change, designated leadership, resource mobilization inclusion of all stakeholders, clear guiding principles, an iterative plan linking flexible timetables to phases for curriculum development, engagement in skills training for the cultivation of future leaders, and extensive communication.