MONITORING OF TUMOR-CELL PURGING AFTER HIGHLY EFFICIENT IMMUNOMAGNETIC SELECTION OF CD34 CELLS FROM LEUKAPHERESIS PRODUCTS IN BREAST-CANCERPATIENTS - COMPARISON OF IMMUNOCYTOCHEMICAL TUMOR-CELL STAINING AND REVERSE TRANSCRIPTASE-POLYMERASE CHAIN-REACTION
My. Mapara et al., MONITORING OF TUMOR-CELL PURGING AFTER HIGHLY EFFICIENT IMMUNOMAGNETIC SELECTION OF CD34 CELLS FROM LEUKAPHERESIS PRODUCTS IN BREAST-CANCERPATIENTS - COMPARISON OF IMMUNOCYTOCHEMICAL TUMOR-CELL STAINING AND REVERSE TRANSCRIPTASE-POLYMERASE CHAIN-REACTION, Blood, 89(1), 1997, pp. 337-344
We studied the efficiency of indirect tumor cell purging via enrichmen
t of CD34(+) hematopoietic progenitor cells from leukapheresis product
s (LP) in breast cancer patients based on immunomagnetic selection of
CD34(+) cells. Detection of tumor cells was made by immunocytochemical
staining. In addition, we evaluated the capacity of cytokeratin 19 (C
K19)-and a novel epidermal growth factor receptor (EGF-R)-specific rev
erse transcriptase-polymerase chain reaction (RT-PCR) for monitoring t
umor cell depletion. LP from 13 breast cancer patients were analyzed.
Twenty-three CD34 selection procedures were performed. A median of 1.4
x 10(10) total nucleated cells ([TNC] range, 0.88 to 3.5 x 10(10)) wi
th a median CD34 purity of 2.5% (range, 0.4% to 6.3%) were entered int
o the selection procedure. Immunomagnetic CD34 enrichment resulted in
a median purity of 83.3% (range, 45% to 95.4%) and a median recovery o
f 73.2% (range, 22% to 95%). Retransfusion of CD34-selected cells afte
r high-dose chemotherapy resulted in a rapid and sustained hematologic
recovery, reaching an absolute neutrophil count of 500/mu L at day +1
0 and platelet count of 20,000/mu L at day +11. Tumor cell depletion w
as quantified by immunocytochemical detection of CK19-positive cells.
By this method, a median tumor cell depletion of 1.9 log (range, 0.7 t
o >3 log) could be demonstrated. Immunocytochemical detection of tumor
cells was more sensitive than RT-PCR, yielding positive results in 87
% of LP (17 to 21) versus 58% positive LP (10 of 17). However, EGF-R-b
ased RT-PCR was much more sensitive than CK19-based RT-PCR (10 of 17 v
1 of 17). Despite highly efficient CD34 selection, tumor cells were s
till detectable after CD34 enrichment using immunocytochemistry and EG
F-R-specific RT-PCR. Thus, this novel EGF-R-specific RT-PCR appears to
be of value as an additional method to detect contaminating breast ca
ncer cells within LP. (C) 1997 by The American Society of Hematology.