PIN1 and nasopharyngeal carcinoma: PIN1 overexpression was also demonstrated in a panel of EBV-positive NPC cell line (C666-1) and xenografts (C15, C17, xeno-2117 and xeno-666) by Western blotting, whereas only weak PIN expression was detected in the immortalized normal nasopharyngeal epithelial cell lines (NP460 and NP69) (Fig 1B).