Clue: Possible cancer treatment initially bought on railway station oddly (10)
Answer: BRYOSTATIN
Explanation: Definition: Possible cancer treatment
[*initially*] **B**(ought) *on* **RY** (railway) ***(station) **[anag: *oddly*] 
*Bryostatins are a group of macrolide lactones from the marine organism Bugula neritina that may play a part in a cure of cancer