Ana-A-Burkitt's lymphomaRef: Robbins Pathologic Basis of Disease, 8th edition, Pg: 259 & 589Explanation:BURKITT LYMPHOMAThere are three clinical types:African (endemic) Burkin lymphoma,Sporadic (nonendemic) Burkitt lymphomaAggressive lymphomas associated with HIV.These 3 types are histologically identical.MorphologyThe tumor exhibits a high mitotic index and contains numerous apoptotic cells, the nuclear remnants of which are phagocytosed by interspersed benign macrophages.These phagocytes have abundant clear cytoplasm, creating a characteristic "starry sky" pattern.ImmunophenotypeThese are tumors of mature B cellsIt expresses surface IgM, CD 19. CD20, CD 10, and BCL6. a phenotype consistent with a germinal center B-cell origin.Unlike other tumors of germinal center origin, this does not express anti-apoptotic protein BCL2.Molecular PathogenesisAll forms of Burkitt lymphoma are associated with translocations of the c-MYC gene on chromosome 8.The translocation partner is usually the IgH locus but may also be the Ig g or y light-chain loci., All endemic tumors are latently infected with EBV, which is also present in about 25% of HIV- associated tumors and 15% to 20% of sporadic cases.Clinical FeaturesEndemic Burkitt lymphoma often presents as a mass involving the mandible and shows an unusual predilection for involvement of abdominal viscera, particularly the kidneys, ovaries, and adrenal glands.Sporadic Burkitt lymphoma most often appears as a mass involving the ileocecum and peritoneum.Burkitt lymphoma is very aggressive but responds well to intensive chemotherapy. (See table below)(Table of Q. 10) Selected Oncogenes, Their Mode of Activation, and Associated Human TumorsCategoryProtooncogeneMode of ActivationAssociated Human TumorGROWTH FACTORSPDGF-j3 chainSIS (official name PBGFB)OverexpressionAstrocytomaOsteosarcomaFibroblast growth factorsHST1OverexpressionStomach cancerINT2 (official name FGF3)AmplificationBladder cancerBreast cancerMelanomaTGF-aTGFAOverexpressionAstrocytomasHepatocellular carcinomasHGFHGFOverexpressionThyroid cancerGROWTH FACTOR RECEPTORSEGF-receptor familyER8B1 (EGFR), ERRB2OverexpressionSquamous cell carcinoma of the lung,GliomasFMS-like tyrosine kinase 3FL 73AmplificationBreast and ovarian cancersReceptor forneurotrophicfactorsRETPoint mutationLeukemia Point mutationMultiple endocrine neoplasia 2A and B, familial medullary thyroid carcinomasPDGF receptorPDGFRBOverexpression,translocationGliomas, leukemiasReceptor for stem cell (steel)factorKITPoint mutationGastrointestinal stromal tumors (GIST) Seminomas LeukemiasPROTEINS INVOLVED IN SIGNAL TRANSDUCTIONGTP-bin dingKRASPoint mutationColon, lung, and pancreatic tumorsHRASPoint mutationBladder and kidney tumorsNRASPoint mutationMelanomas, hematologic malignanciesNonreceptor tyrosine kinaseABLTranslocationChronic myeloid leukemiaAcute 1ympboblastic leukemiaRAS signal transductionBRAFPoint mutationMelanomasWNT signal transductionb-cateninPoint mutationHepatoblastomas,Overexpressionhepatocellular carcinomaNUCLEAR-REGULATORY PROTEINSTranscriptionalActivatorsC-MYCTranslocationBurkitt lymphomaN-WCAmplificationNeuroblastoma, small-cell carcinoma of the lungL-MYCAmplificationSmall-cell carcinoma of the lungCELL CYCLE REGULATORSCyclinsCyclin DTranslocationMantle cell lymphomaAmplificationBreast and esophageal cancersCyclin EOverexpressionBreast cancerCyclin-dependent kinaseCDK4Amplification or point mutationGlioblastoma, melanoma, sarcoma