Ation with genotype see [5], of note, 29 of patients expressed CD66c on more then 50 blasts. Comparison with other MyAg showed that CD66c is more frequently expressed. Coexpression of CD66c with other MyAg was not a usual finding (Table 1, Figure 2). Expression of CD13, CD33 and CD65 tended to be non-random (mutually exclusive) with CD66c (Table 1). Coexpression of CD66c with any 2 of the other MyAg was found in fewer than 4 cases in each combination. Interestingly, mutual order CBIC2 relationship of other MyAg was random, with the exception of CD13 and CD33 coexpression (p < 0.0001) and CD15 and CD65 coexpression (p = 0.0002). The analysis was performed also at different cutoff values (10, 30 and 50 ; data not shown). The same or less significant correlations were also observed at different cutoff values.Cross-blocking of KOR-SA3544 clone with 9A6 clone The moAb clone KOR-SA3544 was not included in Human Leukocyte Differentiation Antigens workshop, but was characterized by Sugita et al [13]. To prevent ambiguous interpretation of our data we extended characterization of KOR-SA3544 clone of CD66c moAb by blocking experiments on CD66cpos blasts. Pretreatment of cells with workshop-typed clone 9A6 moAb completely blocked binding of KOR-SA3544 clone in all 9 leukemic specimens and in granulocytes (data not shown). Cytoplasmic presence of CD66c in ALL blasts We have studied surface and cytoplasmic expression of CD66c in 20 ALL diagnostic samples by flow cytometry. In contrast to findings of Sugita et al [13], we have detected CD66c exclusively in all 8 surface positive cases. None of the 12 surface negative cases stained in cytoplasmResultsFrequency of CD66c and myeloid antigen (MyAg) expression We selected 365 patient's samples obtained at diagnosis of B-precursor ALL with available information on the expression of MyAg CD13, CD15, CD33, CD65 and CD66c. This subcohort represents 96 of all B-precursorPage 4 of(page number not for citation purposes)BMC PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28878015 Cancer 2005, 5:http://www.biomedcentral.com/1471-2407/5/of cytoplasmic CD66cpos100 80 60 40 20 0 0 10 20 30 40 50 60posof surface CD66cFigure 2 illustration of hood B-precursor ALL myeloid antigen positivity in childGraphical Graphical illustration of myeloid antigen positivity in childhood B-precursor ALL. For each antigen, positive cases are represented by a colored form. The areas of the forms roughly correspond to the frequency of positive cases (observed numbers of patients are marked in red) while the shapes are constructed to illustrate the respective coexpressions. An arbitrary cutoff value of 20 is used for all antigens. The CD66c positivity correlates with negativity of any of the following: CD33 (p = 0.002), CD13 (p < 0.0001) and CD65 (p = 0.029). There was a significant correlation between CD33 and CD13 positivity (p < 0.0001) and between CD15 and CD65 positivity (p = 0.0002) whereas the positivity of no other two antigens of the ones shown correlated significantly with each other. Total number of B-precursor cases illustrated is 365.Figure 3 Relationship of surface and cytoplasmic expression of CD66c Relationship of surface and cytoplasmic expression of CD66c. Percentage of surface expression of CD66c in ALL blasts is plotted against cytoplasmic expression (after cell membrane permeabilization). Samples of 20 patients at ALL diagnosis are shown, 12 CD66c negative and 8 CD66c positive. Regression coefficient R2 = 0.FACS-sorted of heterogeneous specimens (lymphoblasts partly positive for C.