B ALL is due to -

Ans. is 'b' i.e., Immature B ceils Acute lymphoblastic leukemia'lvmphomao Acute lymphoblastic leukemia (ALL) encompasses a group of neoplasms composed of immature, precursor B (Pre-B) orT (Pre-T) lymphocytes referred to as lymphoblast.o Majority (85%) of all ALLs are precursor B-cell tumors that typically manifest as childhood "Leukemia" with extensive bone marrow and variable peripheral blood involvement,o The less common precursor T-cell ALLs tend to present in adolescent males as "lymphomas", often with thymic involvement.o Peak incidence of Pre B-celJ ALL is evident between 3-5 years and ALL is the most common childhood cancer.o PreT-cell ALL occurs in adolescent male.o Morphology of tumor cell (lymphoblast).Having scant cytoplasm and nuclei somewhat larger than those of small lymphocytes.The nuclear chromatin is delicate and finely stippled and nucleoli are either absent or inconspicuous.Contain cytoplasmic aggregates of Periodic acid schiff tPASi positive material.Immunophenotvpe of B cell ALLImmunophenotvpic classification of acute lymphoblastic leukemiaPre T cell ALLTdT, CD2. CD3, CD5XD4, CD7, CD8Early pre BTdT, DR, CD 10, CD 19, CD24Pre B cellTdT, DRXD10, CD19, CD20, CD24, CIgB CellDR, CD 19, CD20, CD24, SIg