PRPF31 and nasopharyngeal carcinoma: Two studies have investigated PRPF31 expression from total RNA in blood, similar to our approach, and found that the levels in NPC were intermediate between RP individuals and the control group (n = 7 RP, 3 NPC, 8 controls) [39], and that PRPF31 expression levels were reduced in RP compared to controls (n = 3 RP, 9 controls, no NPC) [31].