Philadelphia chromosome is
Correct Answer: Chromosome 9-22 translocation
Description: Ans. a (Chromosome 9 - 22 translocation). (Ref. Harrison's Medicine, 18th/ ch.83, Table 83-2)# Specific translocation seen in CML is the Philadelphia chromosome (Ph) which is derived from a reciprocal translocation between chromosomes 9 and 22 with the breakpoint joining the sequences of the ABL oncogene with the BCR gene.# The first reproducible chromosome abnormality detected in human malignancy was Philadelphia chromosome. Seen in CML. This occurs by reciprocal translocation involving ABL oncogene, a tyrosine kinase on chromosome 9 being replaced in proximal to BCR on chromosome 22 t (9, 22).# Consequences of expression of BCR ABL gene product is activation of signal transudation pathways, leading to cell growth independent of normal external growth factors.# Robertsonian translocation is translocation between two acrocentric chromosomes & it most often involves 14 & 21 Reciprocal transactions involve mutual exchanges between any 2 chromosomes.Also note:# Cytogenetic changes have been particularly well studied in (1) leukemias, e.g., Philadelphia chromosome translocation in CML ; and (2) lymphomas, e.g., translocations of MYC in Burkitt's .These and other translocations are useful for diagnosis, classification, and prognosis.Representative Oncogenes at Chromosomal TranslocationsGene (Chromosome)TranslocationMalignancyABL (9q34.1)-BCR (22q11)(9;22)(q34;q11)Chronic myeloid leukemiaATF1 (12q13 )-EWS (22q12)(12;22)(q13;q12)Malignant melanoma of soft partsBCL1 (11q13.3 )-1gH (14q32)(11;14)(q13;q32)Mantle cell lymphomaBCL2 (18q21.3 )-1gH (14q32)(14;18)(q32;q21)Follicular lymphomaFLI1 (11q24)-EWS (22q12)(11;22)(q24;q12)Ewing's sarcomaLCK (1p34 )-TCRB (7q35)(1;7)(p34;q35)T cell acute lymphocytic leukemiaMYC (8q24 )-IgH(14q32)(8;14)(q24;q32)Burkitt's lymphoma, B cell acute lymphocytic leukemiaPAX3(2q35)-FKHR/ALV (13q14)(2;13)(q35;q14)Alveolar rhabdomyosarcomaPAX7(lp36KHR/ALV(13q14)(1;13)tp36;q14)Alveolar rhabdomyosarcomaREL (2p13)-NRG (2p11.2-14)Inv(2(p13;pll.2-14)Non-Hodgkin's lymphomaRET (10q11.2)-PKAR1A(17q23)(10;17)(q11.2;q23)Thyroid carcinomaTAL1(1p32)-TCTA (3p21)(1;3)(p34;p21)Acute T cell leukemiaTRK (1q23-1q24 (1q31)Inv1(q23;q31)Colon carcinomaWT1 (11p13)-EWS (22q 12)(11;22)(p13;q12)Desmoplastic small round cell tumor
Category:
Unknown
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now