PLK4 and malignant colon neoplasm: Given KLF14 transcription is significantly reduced, whereas Plk4 transcription is increased in a large number of human breast and colorectal cancers (Supplementary Tables 1 and 2), and a previous study also discovered Plk4 overexpression in human colon cancers38, we next performed immunohistochemistry staining of KLF14 and Plk4 protein on tissue chips containing paired tumour and peri-tumour normal specimens of human breast and colon cancers.