PEBP1 and nasopharyngeal carcinoma: The IHC staining results revealed that strongly positive p-Ser153 RKIP staining was observed in the cytoplasm of NPC tumor cells for 80.0 % (72/90) of patients in the radiosensitive group (Fig. 1a and d) and NNET (Fig. 1c and f); by contrast, negative p-Ser153 RKIP staining was observed for 73.3 % (72/90) of patients in the radioresistant group (Fig. 1b and e).