PDIA3 interacts with the lectin chaperons; calnexin and calreticulin to surveythe folding of newly synthesized glycoproteins by the addition of N-linkedglycans. PDIA3 is also involved in transcaltachia signaling cascades andimmunogenicity. The purpose was to determine if there were any changespresent in the nucleotide sequence of the Pdia3 gene. To study this, fourprostate cell lines were examined by Sanger sequencing, two malignant(LNCaP, PC3) and two normal (PNT1A, PNT2). These were to be compared tothe nucleotide sequence from nine formalin fixed paraffin-embedded (FFPE)samples of different Gleason score and the sequence from three FFPE samplesof normal prostate tissue chosen from the Örebro Radical Cohort. The obtainedsequences were then analysed with several bioinformatics tools to determine ifthere were any changes present. The nucleotide sequence obtained from thesequencing indicated that none of the cell lines expressed the most redundantisofrom; CRA_c, but instead CRA_a and CRA_b. Surprisingly, the two normalcell lines (PNT1A and PNT2) produced similar scores in BLAST search forboth the CRA_a and the CRA_b isoforms. Software analysis of the translatedsequences predicted that LNCaP expressed a membrane bound form PDIA3while PC3 expressed a cytoplasmic variant of the protein. To confirm this,another sequencing reaction was performed. The second results indicated thatall cell lines expressed the same isoform, but that the isoforms were localizedto different intracellular compartments.