PMC6930920_01
Extensive CIC formation in heterogeneous cancer tissue. (A) Representative image for HER-2 staining. Inner cells of CIC structures are indicated with red asterisks. Scale bar: 100 mum. (B) Representative image for a typical CIC depicted with E-cadherin staining. Inserted picture of the top merged image is a schematic cartoon for the indicated CIC structure. Scale bar: 20 mum. (C,D) Histogram plots of cell size (C) and cell circularity (D) for (A).
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F1
Biopsy tissues displayed a large degree of cellular heterogeneity with tumor cells varying significantly in shape and size (Figure 1) and a high rate of Ki-67 positivity indicating active proliferation (Figure 2). Like E-cadherin, HER-2 staining labeling cell boundary depicts a number of unique structures morphologically resembling CIC structures (Figures 1A,B).
Images of Ki-67 staining indicating active cell division. (A) representative image for breast cancer tissue with Ki-67 staining. (B-F) zoomed in images for boxed regions in (A). The scale bars are 400 and 100 mum, respectively.
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F2
Biopsy tissues displayed a large degree of cellular heterogeneity with tumor cells varying significantly in shape and size (Figure 1) and a high rate of Ki-67 positivity indicating active proliferation (Figure 2).
Complex morphologies of CIC structures. (A) One cell was internalized. (B) abnormal nucleus of the outer cell. (C) Two cells were internalized, and the nucleus of one of them was missing. (D) The cell enclosing two cells was inside of another cell (yellow arrow) without nucleus. (E) Two cells were internalized, and the nucleus of the outer cell was deformed. (F) Sequential internalization of three cells. Inserted pictures are schematic cartoons for the indicated CIC structures, respectively. Scale bar: 20 mum.
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F3
While most of them contained one cell (Figures 3A,B), some contained two or more (Figures 3C-E), which may have been caused by multiple internalization events or a single internalization event followed by mitotic cell division. Furthermore, some cells seemed to internalize sequentially to form superposition structures (Figure 3F). The outer cell nuclei were generally abnormal (Figures 3B,D) or irregular with some being split or multiple (Figures 3C,E,F), indicating aneuploidy or multi-ploidy, consistent with the report that CIC could induce aneuploidy by blocking cytokinesis of the engulfing cells.