title: [Clinical significance and frequency of the 11q23/MLL genetic molecular alteration in Chilean infants with acute leukemia].
abstract: BACKGROUND
  Acute leukemia (AL) in infants generally shows distinctive biologic features and has a poor prognosis.
  
  
  OBJECTIVE
  To study the frequency of the cytogenetic alteration of 11q23 chromosome or the recombination of MLL gene in infants less than 18 months old, with acute leukemia.
  
  
  METHODS
  We analyzed 37 cases of AL in infants less than 18 months of age diagnosed in Chile from 1989 to 1999. The clinical features and cytogenetic/molecular defects of 11q23MLL gene rearrangement and their influence in prognosis were determined.
  
  
  RESULTS
  There were 18 cases of acute Lymphoblastic leukemia (ALL) characterized by female sex (67%) high presenting leukocyte count (median 99 x 109/L), blast cells with a CD10 negative phenotype (50%) and 11q23/MLL rearrangement (39%). Molecular abnormalities of 11q23 were significantly associated with adverse prognosis, with an event free survival (EFS) of only 14 +/- 12%. Interestingly, infants with germ line 11q23 had a very good outcome with an EFS of 73 +/- 11% (p < 0.025). There were 19 cases of acute myeloblastic leukemia (AML) characterized by male sex (63%) high leukocyte count (median 93 x 109/L), FAB-MS morphology (53%) and 11q23/MLL rearrangement (53%). EFS was very poor, 20 +/- 9% and 33 +/- 4% for rearranged and germinal group respectively (p = NS), due to a high mortality rate during the first month of diagnosis.
  
  
  CONCLUSIONS
  These findings demonstrate that Chilean ALL infants with 11q23 abnormalities have a very poor prognosis. However those with germinal state can enjoy a prolonged disease free survival with the current treatment protocols.
authors.affiliation: Departamento de Medicina, Campus Oriente, Facultad de Medicina Universidad de Chile. mcabrera@mi-mail.cl
authors.forename: M E
authors.initials: ME
authors.lastname: Cabrera
authors.forename: M
authors.initials: M
authors.lastname: Campbell
authors.forename: J
authors.initials: J
authors.lastname: Quintana
authors.forename: M S
authors.initials: MS
authors.lastname: Undurraga
authors.forename: A A
authors.initials: AA
authors.lastname: Ford
authors.forename: M F
authors.initials: MF
authors.lastname: Greaves
mesh_terms: D015139:Blotting, Southern; D002677:Chile / Q000453:epidemiology; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D020732:Cytogenetic Analysis; D018572:Disease-Free Survival; D005260:Female; D015321:Gene Rearrangement / Q000235:genetics*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000401:mortality; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000401:mortality; D011379:Prognosis; D011446:Prospective Studies
vernacular_title: Significado clínico y frecuencia de la alteración genético/molecular 11q23/MLL en lactantes con leucemia aguda en Chile.