CALR and nasopharyngeal carcinoma: Furthermore, multivariate regression analysis showed (Table 2) that CALR protein expression was significantly related to the PFS and OS, NPC patients who had high expression of CALR protein, had a shorter PFS (HR= 2.564, P = 0.013) and OS (HR= 3.179, P =0.003), while the age, gender, metastasis and clinical staging had no significant association with PFS or OS of patients through COX multi-factor regression.