Figure 1

Cellularity classification. Hematoxylin and eosin (H&E) staining results showing (A) low (< 20%), (B) medium (20–50%), and (C) high (> 50%) cell contents. (D) Vascular invasion. (E) Elastica van Gieson (EVG) staining showing a small vascular invasion. Clefts are formed, and red blood cells are visible in the clefts. (F) Slightly larger vascular invasion with EVG staining, showing almost no cleft space. (G) Myxoid area in an undifferentiated sarcoma observed via H&E staining. (H) Sickle-shaped blood vessels observed via H&E staining. (I) Cluster of small sickle-shaped blood vessels observed via H&E staining. (J) Round-shaped blood vessels observed via H&E staining. (K) Anti-CD31 staining of the round-shaped blood vessel in panel j; the lumen is covered. (L) Anti-αSMA staining of the round-shaped blood vessel in panel j; positive cells are uninterrupted around the vessel. (M) Sickle-shaped blood vessels observed via H&E staining. (N) Anti-CD31 staining of vessels in panel m; the clefts are covered by the vascular endothelium, indicating a vascular lumen rather than an artifact. (O) Anti-αSMA staining of the sickle-shaped blood vessels in panel m, showing intermittent coverage by positive cells, mainly in the vascular branches. (P) INFa infiltration pattern with a clear border between the tumor and surrounding connective tissue observed via H&E staining. (Q) INFc infiltration pattern with tumor cells infiltrating into the surrounding connective tissue observed via H&E. (R) Differences in tail-like infiltration length (TIL) measurements between the macroscopic and microscopic tumor areas, showing gross (green line) and microscopic (red line) coverage extents.