Ewing Sarcoma tumor cells express CD34: implications for autologous stem cell transplantation

Abstract

The significance of tumor cell contamination in marrow and peripheral blood stem cell (PBSC) collections of patients with solid tumors remains controversial. Various methods have been developed to purge tumor cells from autologous stem cell products, including CD34 þ selection. PBSC harvests from patients with Ewing family of tumors (EFT) were analyzed for contaminating tumor cells prior and after CD34 þ selection using reverse transcriptionpolymerase chain reaction (RT-PCR) and flow cytometry (FC) analyzes. The expression of CD34 was studied by RT-PCR and FC in 14 primary tumors and 13 PBSC harvests, respectively. Tumor cells were identified in the harvests by both methods. In two patients, contaminating tumor cells were evident by RT-PCR only after positive selection. FC analysis confirmed a higher level of tumor cells in the CD34 þ fraction. In an attempt to explore this finding, expression of CD34 was detected in 93% of primary tumors and 67% of contaminated harvests. As CD34 is expressed on EFT cells, these cells may be enriched following CD34 þ selection of harvests, although the total number of tumor cells is reduced. Other methods of purging, rather than CD34 þ selection, should be explored in patients with EFT undergoing autologous stem cell transplantation.

Flow cytometric detection of Ewing sarcoma cells in peripheral blood and bone marrow

“…One group has reported that a subset of Ewing sarcoma cells may express CD34 [19]. In the current study, exclusion of CD34+ cells in our six-color panel did not eliminate the observed CD99+CD45- signal.…”

CD34 cells in somatic, regenerative and cancer stem cells: Developmental biology, cell therapy, and omics big data perspective

“…Hematopoietic cancer cell lines were reported to contain both, CD34 − and CD34 + subpopulations that were individually capable of generating tumor in NOD/LtSz‐scid/scid mice . This study demonstrated the presence of CD34 + subpopulation in several blood cancer cell lines, a feature that was earlier reported in several types of solid tumors . Compared to the CD34 − cell population CD34 + cells demonstrated higher rates of proliferation and capacity to generate colonies in methylcellulose based medium.…”

Ewing sarcoma family of tumours: unusual histological variants and immunophenotypic characteristics

“…46 CD34 has been reported to be negative on immunohistochemistry 27,44 but positive on RT-PCR. 48 Expression of p53 is seen in approximately 10% of ESFT and appears to be associated with an extremely poor outcome. 49 Cyclin D1 is often expressed and if negative, is associated with increased patient survival.…”