Autologous Bone Marrow Transplantation - Blog Science Connections

512 Tumor Cell Detection
Table 3. Incidence of Tumor Cells Detected in the Marrow by
Immunofluorescence as a Function of Disease Extension
Tumor Cells in the Marrow
Detected by Immunofluorescence
Clinical Stage Present Absent Total
Limited disease 7 (29%) 17 24
Extensive disease 9 (60%) 6 15
Total 16 (41%) 23 39
or LCA3 were found in 7 out of 24 patients with limited disease and in 9 out of
15 patients with extensive disease.
A remarkable heterogeneity in the tumor recognition was noted. Anti-
LCA1 recognized tumor cells in 11 (68%) of 16 of the 16 marrows studied,
and anti-LCA2 and LCA3 each recognized 7 (43%) out of the 16.
DISCUSSION
The goal of the present study was to investigate the human tumor stem
cell assay and indirect immunofluorescence with anti-LCAl, LCA2, and LCA3
in the detection of SCLC metastases in the bone marrow.
In this study, we have not found a good correlation between morphological
evidence of marrow involvement by SCLC and growth of tumor
colonies in soft agar; the sensitivity ([true positives]/[true positives plus false
negatives]) being 0.2. Nevertheless, there were seven samples of histologically
negative marrow in which the tumor stem cell assay grew colonies. Even
if this system has a low sensitivity, probably because of the low plating
efficiency of the tumor cells, it has the advantage of documenting the
presence of viable clonogenic cells in the bone marrow.
All patients with morphological evidence of marrow involvement had
SCLC cells identified by anti-LCAl, LCA2, or LCA3 antibodies, the sensitivity
of the indirect immunofluorescence being 1. Anti-LCAl, LCA2, and LCA3
were unreactive with 15 normal bone marrow samples but did react with 11
bone marrow samples negative by conventional morphological methods.
The antigenic heterogeneity found on the cell surface using anti-LCAl, LCA2,
and LCA3 highlights the advantage in using a panel of MAbs with different
specificities. Bone marrow involvement was found in 24% of 24 patients who
had otherwise limited disease. A positive pretreatment bone marrow is an
unfavorable prognostic indicator both for survival and for duration of
remission (1). The prognostic significance of bone marrow micrometastases
detected by indirect immunofluorescence in patients with limited disease and
morphologically negative bone marrow is not yet known. A prospective trial
might address this question.
This experiment using human tumor stem cell assay and indirect