Every year about 10,000 children develop cancer in the US. Acute lymphoblastic leukemia (ALL), a rapidly progressing blood cancer, accounts for a quarter of these childhood cancers. Normally, cells in the bone marrow (the spongy material inside bones) develop into lymphocytes (white blood cells that fight infections), red blood cells (which carry oxygen round the body), platelets (which prevent excessive bleeding), and granulocytes (another type of white blood cell). However, in ALL, genetic changes in immature lymphocytes (lymphoblasts) mean that these cells divide uncontrollably and fail to mature.
Eventually, the bone marrow fills up with these abnormal cells and can no longer make healthy blood cells. As a result, children with ALL cannot fight infections. They also bruise and bleed easily and, because they do not have enough red blood cells, they often complain of tiredness and weakness. With modern chemotherapy protocols (combinations of drugs that kill the fast-dividing cancer cells but leave the normal, nondividing cells in the body largely unscathed), more than 80% of children with ALL live for at least 5 years.
Source: Michael J. Sorich et al, St. Jude Children's Research Hospital, Memphis, Tennessee. PLoS Med. 2008-04-15
Acute lymphoblastic leukemias and hispanic population
Acute leukemias (AL), especially acute lymphoblastic leukemias (ALL), have been reported with a very elevated incidence within the Hispanic pediatric population in the United States (USA). For children under the age of 15 years, the incidences of ALL worldwide varies between 20-35 cases per million, whereas the incidence of ALL for Costa Rica and in Mexico City (also known as the Distrito Federal) and for the Hispanic populations that live in the USA are greater than 40 cases per million.
Source: María L Pérez-Saldivar et al, Hospital de Pediatría, Centro Médico Nacional México D.F., México BMC Cancer 2011-08-17
Philadelphia chromosome
The philadelphia chromosome (Ph1) is detectable in 2% to 5% of children with acute lymphoblastic leukemia (ALL) . The detection of a philadelphia chromosome remains a major prognostic factor of induction failure. Despite the steady improvement in the management of ALL in children, Ph1-ALL is associated with high rates of relapse or resistance to treatment. This disease is heterogeneous in terms of clinical parameters such as leukocyte count, age at diagnosis, and initial steroid response [4,6]. A slow early response to conventional therapy has also been reported as indicative of a poor prognosis.
Source: Virginie Gandemer, University Hospital of Rennes, Rennes, France, BMC Cancer 2008-09-15