PLK1 and rectal cancer: While there are a number of publications regarding prognostic effects of PLK1 in various human malignancies [6,16], this is the first report to our knowledge, investigating PLK1 expression in different sampling sites from the same tumour, and demonstrating that upregulated PLK1 expression in the periphery of the primary tumour correlates with inferior survival outcome in rectal cancer, and is independent of proliferative marker Ki67.