Macrophage traits in cancer cells are induced by macrophage-cancer cell fusion and cannot be explained by cellular interaction

Table 1 Size and number of alleles from short tandem repeat (STR) analysis

STR marker	Hybrids	Macrophages	MCF7 cells
AMEL	105, 110/2	105, 110/2	105/1
DXYS218	323, 327, 331/3	327, 331/2	327/1
SRY	204/1	204/1	-
X22	205, 209, 224/3	205, 224/2	209/1
XHPRT	277, 289/2	277/1	289/1
DXS6803	123, 126/2	126/1	123/1
DXS6854	107/1	107/1	107/1
D13S305	449/1	445, 456/2	448/1
D13S628	455/1	456/1	455/1
D13S634	394, 399/2	394/1	399/1
D13S742	287/1	262, 290/2	286/1
D13S797	196, 200/2	196/1	196, 200/2
D18S386	351, 355, 388, 392/4	355, 388 /2	351, 392/2
D18S390	338, 342/2	342/1	338, 342/2
D18S391	160/1	160/1	160/1
D18S535	475, 483, 487/3	475, 487/2	483/1
D18S819	251, 254, 262/3	251, 254/2	262/1
D18S976	185/1	186, 189/2	185/1
D21S11	253, 267/2	245, 255/2	253, 267/2
D21S1246	293, 297, 318/3	293, 318/2	293, 297/2
D21S1409	203, 210, 214/3	210, 214/2	203, 214/2
D21S1411	307, 312/2	299, 332/2	307, 312/2
D21S1435	375, 383, 387/3	375, 383/2	375, 387/2
D21S1444	314, 318/2	318/1	314, 318/2

STR analysis was used to determine the DNA profile of M macrophages, GFP-labeled MCF-7 breast cancer cells, and MCF-7/macrophage hybrids. A total of 24 loci on X and Y chromosomes as well as chromosomes 13, 18 and 21 were used in this analysis. The macrophages originated from M2-activated monocytes harvested from male blood donors and contained Y chromosome. MCF-7 is a breast cancer cell line isolated originally from a female patient. Of 24 markers, 17 were of the same allelic size in MCF-7/macrophage hybrids. For several loci at least one allele was common to macrophages and MCF-7 cancer cells represented in the hybrids. Sex-determining region Y gene (SRY) is one of the markers found in MCF-7/macrophage hybrids, indicating that these cells originate from fusion between macrophages and MCF-7 cells. Note that the hybrids contain the same size of alleles on the X-chromosome markers as do macrophages and MCF-7 cells

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