TYMS and glioblastoma: Interestingly, among these 29, thymidylate synthase (TYMS) was the second best hit on the list (Table 4, GTI score 35, COPA score 105, OS score 1864, ORT score 1646), indicating high expression of this gene in many but not all glioblastomas, but generally low expression levels across the vast majority or all of the normal samples.