We used a DIGE (two-dimensional fluorescence difference in gel electrophoresis) quantitative proteomic analysis to search for differentially expressed proteins between the ovarian cancer cell line SKOV3 and SKOV3-TR30, a cell line with a 27-fold increase in paclitaxel resistance over its parental SKOV312, and found a remarkably decreased expression of UBC13 (UBE2N, ubiquitin conjugating enzyme E2 N) in SKOV3-TR30 cells. The gene discussed is UBE2N; the disease is ovarian cancer.