关键词：癌症;治疗;药物;治疗;分子生物学;患者;临床研究
摘 要：Despite recent advances in deciphering the molecular pathways that trigger cancer and its progression, progress in developing therapies that effectively target those pathways has been hampered by their complexity. Researchers are finding that many cancer pathways have backup or bypass pathways that foster drug resistance. Consequently, targeted therapies that initially are quite effective in certain patients eventually stop working. In addition, many therapies appear to work best when they are used in combination with various treatment modalities. Combining investigational cancer therapies early in their development is thought to be a promising strategy for identifying cancer treatments that will be effective in the long term, especially when a combination targets multiple pathways and byways in the development or progression of cancer, or more than one step in a pathway, potentially conferring greater benefit than a therapy directed at a single target.