Fig. 5

 H&E and immunohistochemistry (IHC) staining for pyruvate kinase M2 (PKM2) expression in breast cancer tissues and positive control. a). H&E staining of low PKM2 expression in breast cancer tissue. b). H&E staining of high PKM2 expression in breast cancer tissue. c-k). IHC staining of PKM2 manifested mainly in the nucleus in: c). Positive control tissue (colon tissue). d). Luminal A breast cancer subtype (low expression level ≤ 4). e). Luminal A breast cancer subtype (high expression level > 4). f). HER2-enriched breast cancer subtype (low expression level ≤ 4). g). HER2-enriched breast cancer subtype (high expression level > 4). h). Triple positive breast cancer subtype (low expression level ≤ 4). i). Triple positive breast cancer subtype (high expression level > 4). j). Triple negative breast cancer subtype (low expression level ≤ 4). k). Triple negative breast cancer subtype (high expression level > 4). Arrows indicate the positively stained cells. Scale bar: 400 × (40X objective lens x 10X ocular lens = 20 μm)