Association of tumor grade, stage, recurrence, disease progression and serum sodium levels with FAM81A or PCSK6 relative copy numbers. (A) Patients with recurrence and disease progression had significantly lower FAM81A relative copy number than those without recurrence and disease progression (P=0.0010 and P=0.0041, respectively). (B) Patients with pT1 stage, recurrence and disease progression had significantly lower PCSK6 relative copy number than those without pT1 stage, recurrence and disease progression (P=0.0196, P=0.0352 and P=0.0009, respectively). The diamonds show the mean (long horizontal line) and 95% confidence interval of the relative copy number. (C) Patients with lower PCSK6 copy number had significantly higher sodium levels in blood than those with higher PCSK6 copy number (P=0.0165). (D) A positive correlation between PCSK6 relative copy number and serum sodium levels was identified in linear regression analysis (P=0.0162). FAM81A, family with sequence similarity 81 member A; PCSK6, proprotein convertase subtilisin/kexin type 6.