autologous blood and marrow transplantation - Blog Science ...

Ross et al.
that the capture antibody used in the TEC system may not bind to all tumor cells,
thereby resulting in false-negative TEC results. For these reasons, ongoing
experiments are analyzing the addition of additional antitumor cell antibodies to
the existing formulation.
Other groups have recently reported on a variety of methods to accomplish
tumor enrichment. 14-17
These methods vary considerably with regard to efficiency
of cell capture, sensitivity and specificity, and ease of use. For example, Naume et
al. 16
reported the enrichment of epithelial-derived tumor cells using mAbs coupled
to magnetic beads. While efficient in cell capture, the adherence of the beads to the
cells can cause difficulty in subsequent immunostaining and morphologic verification.
Bead removal procedures that rely on enzymatic treatments often severely
disrupt the cell integrity, thereby rendering the cells nonviable and morphologically
disrupted. These problems are also encountered in methods that use magnetic
particle separation technology against intracellular components such as
cytokeratins.
It is possible to enrich tumor cells by using magnetic ferrofluids followed by
multiparameter fluorescence activated cell sorting. 17
However, due to the limits of
cell detection sensitivity and specificity in the cell sorting procedure, a significant
level of false-positives in normal donor specimens has been reported.
Another approach has been to isolate tumor cells by negative depletion of
hematopoietic cells. 16
This method has the advantage of leaving the tumor cells
free of capture antibody, magnetic particles, and presumably viable. However, if
hematopoietic cell depletion is efficient, the possibility exists that the few
remaining tumor cells may be difficult to capture for subsequent analysis.
For these reasons, we have found that the avidin-biotin selection system, when
used in conjunction with an epithelial-associated antibody, is easy, efficient, and
reproducible for the enrichment of breast cancer cells. The use of such a system
may result in the more accurate assessment of MRD in autoSCT grafts from
patients with breast cancer.
REFERENCES
1. Joshi SS, Novak DJ, Messbarger L, et al.: Levels of detection of tumor cells in human
bone marrow with or without prior culture. Bone Marrow Transplant 6:179, 1990.
2. Vredenburgh JJ, Peters WP, Rosner G, et al.: Detection of tumor cells in the bone mar­
row of stage rv breast cancer patients receiving high-dose chemotherapy: The role of
induction chemotherapy. Bone Marrow Transplant 16:815-821, 1995.
3. Fields KK, Elfenbein GJ, Trudeau WL, et al.: Clinical significance of bone marrow
metastases as detected using the polymerase chain reaction in patients with breast cancer
undergoing high-dose chemotherapy and autologous bone marrow transplantation. J Clin
Oncol 14:1868-1876, 1996.
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