Expression of the thymidine phosphorylase gene in epithelial ovarian cancer

Thymidine phosphorylase (TP) is associated with angiogenesis and the progre ssion of solid tumours. High intracellular levels of this enzyme indicate i ncreased chemosensitivity to pyrimidine antimetabolites, TP gene expression in 56 cases of epithelial ovarian cancer (27 of serous, 10 mucinous, 12 en dometrioid, five clear cell and two undifferentiated) were analysed by poly merase chain reaction of RNA after reverse transcription. These included ei ght of low malignant potential. Twenty were stage I, four stage II, 27 stag e III and five stage IV. The level of TP gene expression was presented by t he relative yield of the TP gene to the beta 2-microglobulin gene. TP gene expression ranged from 0.19 to 5.38 (median 0.93). The value of TP gene exp ression in stage Ill-IV was significantly higher than that of TP gene expre ssion in stage I-II (P = 0.0005), Histological grade significantly associat ed with TP gene expression (P = 0.008), but histological subtype did not (P = 0.166). A follow-up study of 34 cases after complete resection of the pr imary tumours by surgical operation was performed. TP gene expression of th e cases with recurrence showed significantly higher levels compared to case s without recurrence (P = 0.049). Survival data were available for 47 of th e 56 patients. The prognosis of the patients with high TP gene expression ( equal to, or greater than, median) was to be significantly worse than patie nts with low TP gene expression (less than median) (P = 0.021). The TP gene expression level may play one of the key roles in the biology of ovarian e pithelial cancer and define a more aggressive tumour phenotype. A new thera peutic intervention mediated by TP protein activity is anticipated.