THE 5Q35BP CHROMOSOMAL ABNORMALITY CHARACTERIZES CERTAIN CD30 POSITIVE ANAPLASTIC LARGE-CELL LYMPHOMAS OFFERING A NEW DEFINITION OF MALIGNANT HISTIOCYTOSIS IN CHILDHOOD
C. Nezelof, THE 5Q35BP CHROMOSOMAL ABNORMALITY CHARACTERIZES CERTAIN CD30 POSITIVE ANAPLASTIC LARGE-CELL LYMPHOMAS OFFERING A NEW DEFINITION OF MALIGNANT HISTIOCYTOSIS IN CHILDHOOD, Nouvelle revue francaise d'hematologie, 35(5), 1993, pp. 463-467
Anaplastic large cell CD30 positive lymphomas represent a heterogeneou
s group of lymphomas in which immunocytochemical and molecular investi
gations have demonstrated the existence of malignancies of T, B or und
etermined origin. The recent identification, in a few cases, of a chro
mosomal 5q35 breakpoint may allow distinction of a specific disease. I
n these cases, the 5q35bp has been found to be a permanent abnormality
present in 5 cell lines and associated with various translocations in
cluding most often t(2;5) but also t(7;5), t(5;6) and t(3;5). A primit
ive myelomonocytic origin of these 5q35bp cells is suggested on the ba
sis of the following arguments: i) they spontaneously express CD68; ii
) they reduce tetrazolium blue; iii) they express the c-fms proto-onco
gene which encodes the macrophage growth receptor (CSF-1); iv) c-fms,
which is not rearranged, has been mapped to 5q33 close to the 5q35 bre
akpoint; v) treatment by phorboldiester of a 5q35bp cell line (DEL) in
duces immunodependent phagocytosis and modulation of the expression of
c-fms, CSF-1 and TNF alpha. Since some 5q35bp cell lines also present
rearrangements of TCR beta or Ig (jH), these data suggest an ancestra
l stem-cell origin, prior to T, B or myelomonocytic differentiation. W
hatever its origin, the 5q35bp abnormality is mainly encountered in ch
ildhood malignancies. As it is constantly associated with the clinical
and biological manifestations of a condition recognized by pediatrici
ans as malignant histiocytosis, 5q35bp may today represent the best cr
iterion for the identification of malignant histiocytosis in childhood
.